Mexiguin's original design was created in 2012 on a sticky note. He originally had 2 dots for eyes, no belt, and had a guitar!
Mexiguin was an idea Joe Kozdra had in the 5th grade and although he never forgot about Mexiguin, he never planned to do anything more with it. When interviewing CH Greenblatt for a podcast, he asked Carl if he'd hear out this proposal for a show about a clumsy penguin, an angry fish, and clueless sloth, he responded with positive thoughts and from them forward, Kozdra lifted the Mexiguin project off the ground.
Although Mikey's sloth appearance is commonly referred to as Sid the Sloth from Ice Age (2002), Mikey is a completely different character who just happens to be the same animal, which accurately is a prehistoric sloth.
Mexiguin was originally spelled, "Mexa-guin"
Fish Taco was originally named "Fish Burrito"