This is how Mismatch the Monster (Animatronic version of Mismatch) looked before he got messed up by his pizza addiction.

I made some concept changes for him, namely that his tail would have had a hydraulics system in it to keep him standing, since he has a lot of tall features that would otherwise put him off balance. Because of this, he couldn't really walk around like the others.

He was given a mechanism for walking around, but the only way was if he either had the tail wheeled around or detached. This was never properly implemented before he was disassembled.

Several weeks of kids shoving pizza into his mouth and parts later, and you get the next picture! Sort of.