In Frostburn Canyon, an error message can be found on a monitor with a humorous message stating that the user has damaged their computer due to viewing pornography.

The full message reads:

Torgue vending machines in the Campaign of Carnage DLC all have 80085 typed into the selection box, an obvious reference to the juvenile joke of spelling the word "BOOBS" out on a calculator.

The Bane's vocal effects will still play even after lowering all of the game's volume settings.

During a second playthrough on "True Vault Hunter Mode", after the chapter "Where Angels Fear to Tread", the player can go to Claptraps Place and find an event item in the fireplace called "Geary's Unbreakable Gear" with the description "Only a brisk walk to Eridium Blight will reward the courier". The player must then travel to Mount Hellsfont, located in the northwest corner of Eridium Blight without dying, using a fast-travel station, or riding in a vehicle spawned from a "Catch-A-Ride" station. If the player is successful, they'll encounter a special enemy named Geary. If the player lets Geary attack them, he'll steal the gear and jump into the lava. This will cause three Rakks to appear and drop three loot chests, one of which will have purple gear. This is a reference to "The Lord of the Rings" book trilogy by J.R.R Tolkien, and the journey to Mount Doom.

The Baby Maker SMG explodes into two smaller versions of itself when reloaded. The chances of spawning a pink or blue variation are actually based on US birth statistics for females and males.

The optional mission in Sir Hammerlock's Big Game Hunt, "Still Just a Borok in a Cage", is a reference to The Smashing Pumpkins song, "Bullet With Butterfly Wings." More specifically it's a reference to lyrics for the chorus, "Despite all my rage, I am still just a rat in a cage."

The side quest "Raiders of the Last Boss" in the Tiny Tina's Assault on Dragon Keep DLC is a clear reference to the Indiana Jones movie "Raiders of the Lost Ark."

Handsome Jack had dialogue recorded for the New-U Station revival taunts, but they were unused in the final release.

The inside cover artwork for the game was based on artist Olly Moss's art style of his homages to various franchises, however, the clouds in the artwork were taken directly from one of Moss's own pieces; from his Star Wars: The Empire Strikes Back fan poster.

When Moss found out, he took to Twitter to express his disappointment, however, Gearbox CEO, Randy Pitchford, soon contacted him and apologized for the incident.

The sidequest, "Too Close for Missiles", contains a large number of reference to the film "Top Gun". The quest starts after talking to Loggins (a reference to Kenny Loggins, the writer of the song "Danger Zone" from the film's soundtrack) outside of Ellie's garage. During the mission, Loggins will repeatedly call the player "Goose", in reference to Maverick's wingman. The mission involves gathering volleyballs and gasoline to light a volleyball net on fire. Following that, 3 NPCs known as Shirtless Men spawn and attack the player. All of the objectives reference the infamous sand volleyball scene from the film. Loggins himself also says "Danger zone" multiple times during the quest.

The side mission "Rocko's Modern Strife" is a reference to the show Rocko's Modern Life.

Tiny Tina's Assault on Dragon Keep contains a reference to the YouTube user "Bro Team Pill". At the end of the optional mission "My Dead Brother", one of the mission completion messages reads "Bro Team Kill".

In a Reddit AMA, Borderlands 2 Lead Writer Anthony Burch said his inspiration for creating the NPC Face McShooty, the character that demands you shoot him in the face, was the "Close Range" video on The Onion, featuring a fictional video game in which the only gameplay is shooting people in their faces.

"That was mine. I saw this video...and thought it was hilarious, and thought we could play off the idea with Face McShooty." -Anthony Burch

The Bane side mission, and weapon, are both based off of the 1950's Western movie "Winchester '73" starring James Stewart. The movie revolves around a cursed rifle that leads to the death of anyone possessing it.

Tiny Tina's lazy eye is actually a bug in the software. Instead of fixing her eye tracking, the developers thought that it fit with her character, so they decided to leave it in the game.

Mister Torgue is censored by a device in his voicebox, rather than being edited later. In his own words:

The red flavor text for the Buffalo gun refers to three notable linguistic constructions:
a sentence that uses the word "buffalo" 9 times and is still grammatically correct, a sentence that repeats the word "had" 11 times to illustrate the importance of punctuation, and a Chinese poem that tells a story using a total of 92 words, which are all pronounced in varying tones of "Shi".

The commando for Borderlands 2, Axton, has been confirmed as bisexual by Borderlands 2 lead writer Anthony Burch.

The "these pretzels suck" and Butt Stallion dialogue spoken by Handsome Jack were ad-libbed by voice actor Dameon Clarke. Writer Anthony Burch was upset that these became Handsome Jack's most popular lines as he had no hand in writing them.

There is a Shotgun in the game called 'Dog'. In the game's code, its file name is "Thre Dog", and its special weapons effect reads, "Because one barrel ain't enough, and two is too few." This is likely a reference to the character "Three Dog" from Fallout 3, who says "Three Dog, because one dog ain't enough and two is too low, it's Three Dog!"

In Sanctuary, there is a chance that an NPC will say "I used to be a Vault Hunter like you, until I took a bullet to the knee." This is a reference to the infamous "I took an arrow in the knee" meme from The Elder Scrolls V: Skyrim.

There is a skill for the Mechromancer called "20% Cooler" This is a Reference to the TV Series "My Little Pony: Friendship is Magic" where the character "Rainbow Dash" says "It needs to be about 20% Cooler".

There is a side mission in the Tiny Tina DLC called "Lost Souls." In the mission, the player helps an undead warrior by collecting souls at camp fires, just like in Dark Souls.

The mission title "Hungry like the Skag" refers to a Duran Duran song, Hungry Like the Wolf, as Skags are wolf/dog-like creatures in the game.

In the Hammerlock DLC there is a side quest "The Rack Dahlia Murder". The mission title is a reference to the unsolved 1947 Black Dahlia murder that occurred in California.

There is a unique relic in the game called the "Deputy's Badge" which is awarded for finishing the mission "The Showdown". Part of its description reads "Who the hell shot me?", a reference to the Bob Marley song "I Shot The Sheriff", the chorus for which begins with "I shot the sheriff, but I did not shoot the deputy."

In the mission Assassinate the Assassins, the Assassins are called "Wot", "Reeth", "Rouf" and "Oney". "Wot", "Reeth" and "Rouf" are anagrams of "Two", "Three" and "Four" while "Oney" is just "one" with a "y" on the end.

The skin "Vault Dweller" for the Siren is a reference to the outfits worn by the members of the vaults from the Fallout series. It follows its color pattern with blue body and yellow highlights.

In the Caustic Caverns, across the acid water, there is a small island with a Knight named Solitaire sitting on a ledge in front of a bonfire. White phantoms are also sitting in front of the bonfire. This is a reference to Dark Souls, with Solitaire being a reference to the knight Solaire of Astora.

While fighting enemies as Axton, he may say "And YOU get a bullet, and YOU get a bullet! EVERYONE gets a bullet!" - a reference to Oprah Winfrey's energetic nature and giving audience members gifts.

There is an enemy called "King Mong", an homage to King Kong, that can be found in the game.

There is a challenge called "It's Not Easy Looting Green" which is a reference to Kermit the Frog's song "It's Not Easy Being Green".

There is a challenge in the 4th DLC called "FUSROHDIE". This is a reference to Skyrim's 'FUS RO DAH' dragon shout.

The mission "The Pretty Good Train Robbery" is a reference to the 1903 film, The Great Train Robbery.

There are several references to the Predator franchise made throughout the game. The skill "Sexual Tyrannosaurs" and "You ugly mother..." are lines said in Predator by Blain Cooper. The achievement/trophy "Unseen Predator" is a reference to the Predators cloaking device. One of the loading screen tips says "if Bleeds we can kill it etc." which is also a reference to the original film.

The challenge titled "Crouching Tiger, Hidden Assault Rifle" is a reference to the movie Crouching Tiger, Hidden Dragon.

There is an enemy called Rakkman located in a cave in the fridge, a homage to the "Batman" series. He may drop a weapon called the Gunerang, a reference to Batman's Batarang. In the second play through, his name is changed to Rakkman Forever, a reference to the film Batman Forever.

In the Tiny Tina DLC there is a side quest called "Winter is a Bloody Business.", which contains several references to Game of Thrones. King Jeffery is a reference to King Joffery, and the throne is similar to the show's Iron Throne, but made of guns instead of swords.

The mission "Won't Get Fooled Again" is a reference to the song of the same name by 'The Who' which is used as the theme tune of television series CSI: Miami. The mission requires the player to solve a murder and upon completion, Marshall Friedman will say a melodramatic one-liner like the main protagonist of the show 'Horatio Caine' does.

Salvador has a head titled 'Breaking Bald' which makes him look like Walter White from the TV show Breaking Bad.

Salvador has a skill called titled "Yippee Ki Yay," a reference to the film series Die Hard, in which this is the catch phrase of the main character.

According to Anthony Burch, the lead writer, Tiny Tina was going to have another quest before it was cut. "After a certain character Spoiler: Roland dies, you get a quest to go tell all of Spoiler:his friends that the person is dead." This would include Tina and, for the first and only time, it would cause her to drop her carefree and insane attitude. She would thank you, give you a new weapon, and then lock herself in her workshop, which she could be heard crying in. Burch did not give a reason for the quest's removal but it is believed that since she lives out in the Tundra rather than at Sanctuary, meaning that players would have to trudge through an area filled with low-level enemies simply for a bit of dialog and a possibly useless weapon, the developers saw it to be not worth it.

Ashly Burch (the voice of Tiny Tina and Bane the cursed gun) is the sister of the lead writer, Anthony Burch. Both siblings produce and star in the web series Hey Ash, Whatcha Playin'?.

One of the skins for Maya is named "Rose Tailor", a possible reference to the character Rose Tyler from the science fiction series "Doctor Who".

Upon exiting Dr. Zed's vending machine, it will sometimes state "Who needs a medical license when you've got style?" This is a reference to the internet meme "Who needs 'X' when you have Swag?"

There is an unlockable color scheme for Zer0 titled "Why So Serious?" This is a reference to the film The Dark Knight and the Batman franchise, as it is a line used by the Joker. The color scheme also uses similar colors to the Joker.

Upon using Zer0's deception skill he may say "How Hilarious. You set off my trap card. Your death approaches." This is a reference to the Yu-Gi-Oh anime.

The side quest "3:10 to Kaboom" is a reference to the movie 3:10 To Yuma.

The challenge "Say Watt again" is reference to the film Pulp fiction where Jules Winnfield says it during an interrogation.

In the side mission "Hell Hath No Fury", after blowing up the dam, Handsome Jack will read out a list of the week's construction casulaties which are: Hartnell, W. Troughton, P. Pertwee, J. Baker, T.

This is a reference to the actors William Hartnell, Patrick Troughton, Jon Pertwee and Tom Baker, all of who played in respective order the character 'the Doctor' in the science fiction series Doctor Who.

At the main menu, Claptrap can be seen entering an outhouse which will then suddenly vanish and quickly land back to the ground, a possible reference to the TARDIS from "Doctor Who" which also travels in a similar fashion.

Occasionally, one of the citizens may say "I'm missing the new episode of Constable What!", a parody of the series "Doctor Who".

Psychos will sometimes say "Never gonna give you up" when they die, a reference to the song "Never Gonna Give You Up" by Rick Astley.

On the radio dials, each number goes up by a hundred until it reaches 800 where then it moves straight to 9001. This is a possible reference to the line "It's over 9000" from "Dragon Ball Z".

The Wildlife Exploitation Preserve may contain two enemies called Pimon & Tumbaa. This is a reference to the characters Timon & Pumbaa from Disney's The Lion King.

In the Scarlet's Booty DLC there are enemies called Mr.Bubbles and Lil' Sis, which are spoofs of Bioshock's Big Daddies and Little Sisters. Defeating Mr.Bubbles without harming Lil' Sis will give the player a special reward.

An enemy that can randomly spawn in the Eridium Blight map is called Donkey Mong, an obvious reference to the Nintendo character "Donkey Kong". Not only is his name just a simple letter replacement, but he attacks the player by throwing barrels, similar to Donkey Kong's first title. Upon killing Donkey Mong, the player will earn the achievement "Definitely An Italian Plumber", a reference to the Mario series, also by Nintendo, as well as an achievement in the first Borderlands, "My Brother is an Italian Plumber".

In the Caustic Caverns is a cave with a number of pixelated blocks. These look very similar to blocks from Minecraft, which break when punched a number of times. Behind these blocks are a handful of enemies called Creepers, including a Badass Creeper, a kind of enemy also found in Minecraft. Among the loot they drop when killed is a new head skin with a pixelated look.

In The Fridge, there is a quest related enemy named Laney White, accompanied by 7 midgets, each named with a foul adjective. This is likely a play off of Snow White and the 7 Dwarves, further implied by the related achievements, "Fairest of Them All", and "It's Off to Hell We Go".

There is a small tent located in the Highlands. Entering the tent triggers a double rainbow to appear on the horizon, with a sound clip from either Handsome Jack or Claptrap imitating the Double Rainbow Youtube video.

The targets of the mission "Splinter Group" are four mutated raiders named Mick, Lee, Ralph, and Dan. This is a play off of the Teenage Mutant Ninja Turtles named Michelangelo, Leonardo, Raphael, and Donatello. The other similarities include their hideout being in the sewers, their name "Splinter Group" after the rat master "Splinter", their surfer-like language ("dude", "brah") and their craving for pizza used to lure them out.

There are a number of QR codes scattered around Pandora. Scanning these codes using a QR code scanner will result in different messages.

Pizza Boxes: "Wise man say, forgiveness is divine but never pay full price for late pizza. -Captain Picard."
Possibly a reference to 4chan, where many pictures of famous characters are misquoted. In this case, a Michelangelo quote from Teenage Mutant Ninja Turtles and Captain Picard from Star Trek: The Next Generation.

In Zed's Pharmacy: "Thank you so much for playing our game, now I'm rich with love AND money! !!Nick Wilson!! Ditto!!!"
A reference to the artist Nicholas W., an artist at Gearbox.

Various Places: "NICK WILSON/ /HO OH"
Same as the previous message, a reference to Nicholas Wilson.

In Borderlands 2, There's a character named Michael Mamaril that will give the player free (and usually rare) loot. This character is based on a real-life person who died at the age of 22. His friend wrote to Gearbox, the game's developers, asking them to do a eulogy using the voice of the fan-favorite character "Claptrap". Gearbox not only fulfilled his request, but also added Michael as a character in Borderlands 2, so he could live on forever in Borderlands.

According to "Inside the Vault: The Art & Design of Borderlands 2" that comes with the special edition of Borderlands 2, when the boss "BNK-3R" makes a noise, it's actually the game's sound designer Joshua Davidson yelling about tea.