Minecraft was originally called "Cave Game".

According to Minecraft's creator Notch, the game's protagonist, Steve, and all other beings in the game are genderless. Animals were designed to be hermaphrodites (for instance, cows/bulls having both horns and udders) to reinforce this. Notch expressed regret in 2012 for refering the protagonist as "Steve" with masculine pronouns, prefering the "up-and-coming" they/them pronoun. He also joked that no gender existing in Minecraft meant that every animal and character in Minecraft is homosexual "because there's only one gender to choose from. Take THAT, homophobes!" It is unclear if Notch still stands by this, as he has since become an outspoken opponent of gay and transgender identities.

Diamonds were originally called Emeralds. Because of the light blue color they had, Notch decided to change the name to diamonds. In the code of Minecraft, Diamonds were still referred to as emeralds until 1.3, which introduced the current item known as Emeralds.

When enchanting an item, the strange symbols used to describe the kind of enchantment is actually a direct usage of the Standard Galactic Alphabet from the Commander Keen series for DOS.

The texts respectively read "Well Played Internets You Are Good", "These Names Will Be Random And Confusing" and "Each Spell Costs Experience Levels" describing the function of the enchantment table.

The Creepers were based on a failed model of a pig. The length and the height of the pig model were accidentally inverted, resulting in a tall mid section with small legs.

Originally, zombies used to drop feathers when killed. This was the result of Notch, the developer of Minecraft at the time, not knowing what zombies should drop.

The in-game NPC Villagers, often referred to as Testificates, were originally planned to be Pigmen, much like the Nether mobs. (Except not undead.) They would have the standard player model like Zombies and Zombie Pigmen, but with a Pig's skin. The second Skin Pack for the Xbox 360 version contains a Pigman skin as a slight nod to this.

Steve once had a beard, but it was removed in the beta update.

"Herobrine Removed" has been added to a number changelogs. Herobrine is a character from a Minecraft "creepypasta" who looks exactly like the player, but has white eyes. It is said that Herobrine is Notch's dead brother, although Notch said himself that he does not have a dead brother. Herobrine never appeared in the game, and it's likely that this line being added to the changelogs is just a joke with the community.

When Soul Sand is directly placed over an ice block, its slow effect is greatly increased, affecting both mobs and players.

One achievement in Minecraft is called "The Lie", which includes making a cake. This is a nod to Portal's famous meme, "The Cake Is A Lie". Also, the achievement for entering the nether in the PC version is called "We Need To Go Deeper", which is a reference of the multi-layered dream based plot of "Inception".

The game was partly inspired by an earlier game by Notch called RubyDung. It was more of a Base-Building type game, like Dwarf Fortress. The old Cobblestone texture came from this game.

Emeralds were originally supposed to be rubies, but they were changed to emeralds due to Dinnerbone (Nathan Adams) being color-blind, making him not able to easily tell the difference between redstone ore and ruby ore.

There's a very rare chance that the "C" and "E" in the Minecraft logo will switch and instead show "Minceraft".

The Snow Golems don't actually have pumpkin heads. They simply wear them as a helmet and their actual faces can be seen by standing in very close proximity to them so that you see through the pumpkin. Shears can be used to remove the pumpkin and cause one to drop it revealing its face, although the pumpkin cannot be put back on the Snow Golem.

Lightning does not have an image file associated with it. It is coded directly into the game engine.

Villagers were inspired by the shop keepers in Dungeon Master 2.

In Minecraft Pocket Edition, there's an unused camera. If hacked into the player's inventory, it can be used to take pictures.

Notch would always drop a red apple when killed in earlier versions of Minecraft.

The Iron Golems holding out roses to baby villagers is a reference to the ancient robots in the animated film Laputa: Castle in the Sky, as is the fact that the Golems are covered in vines.