In the lead-up to the release of Super Villain Island, a piece of concept art titled "Combo Breaker" was posted on the Daily Pop, depicting what appears to be a robot that combined elements from the four villains featured in the island's story (rabbit traits from Dr. Hare, jester traits from Mordred/Binary Bard, artist traits from Black Widow, and pirate traits from Captain Crawfish), as well as what appears to be traits reminiscent of a cowboy. This, combined with an earlier Daily Pop post titled "Perchance to Dream" that suggested the Dream Machine was originally going to have five containment units instead of four, led some fans to believe that El Mustachio Grande (the main antagonist of Wild West Island) was originally going to appear alongside the former four as one of the main villains. While this has never been confirmed, it's worth noting that El Mustachio Grande appeared as one of the answers to the Pop Quiz question "Who is your favorite Poptropica villain?" alongside the four. Additionally, while he does not play a role in the story of Super Villain Island, he does still make a cameo during the elevator sequence alongside various other Poptropica villains.