Professor Mesmo (aka Momo) is a guest character in the All Dogs Go To Heaven: The Series episode "Fearless Fido." He is a hypnotist who hypnotizes guests. Unintentionally, he hypnotized Itchy into being a superhero to him hearing the word "chicken" (or anything that sounds so, like "checkin'") and returning to his normal self when his name is said.

It is unknown who did his voice.

Momo is the only adult human character any of the dogs ever speaks to, that one being Charlie, not including anyone Charlie spoke to in "Charlie the Human."