From the Super Mario Wiki
Fizzlits are small purple blob-like enemies that first appeared in Super Mario Galaxy 2 where they have a tooth-shaped body. They mainly attack by generating an electric puddle around themselves, which will electrocute and damage the player(s) if he or she tries to attack them. However, Fizzlits will only be vulnerable to any of the player's attack when they are in their normal form. In addition, Fizzlits are able to jump around before creating their electric puddles.
Fizzlits appear mostly in industrial levels, such as in Bowser Jr.'s Fearsome Fleet, and in Bowser Jr.'s Boom Bunker. They also make a appearance in Cosmic Cove Galaxy.
Fizzlits reappear in Super Mario 3D World. They are now square-shaped and still retain the same method of attack from before: generating an electric puddle in an attempt to damage players. However, Fizzlits are unable to jump around and will only move sideways when attacking.
Names in other languages
||From "elettro", a prefix related to electronics, and "spalmare", to spread