Fat Guy

Fat Guys are corpulent Shy Guys that debuted in Super Mario World 2: Yoshi's Island.

Super Mario World 2: Yoshi's Island / Yoshi's Island: Super Mario Advance 3
Fat Guys make their first appearances in Super Mario World 2: Yoshi's Island level Lakitu's Wall, and are uncommon enemies throughout the rest of the game. They come in two colors: red (which initially walk but will run if Yoshi stands on them) and green (which are always running). Fat Guys attack by simply walking or running back and forth, much like regular Shy Guys.

Upon ingesting a Fat Guy, Yoshi receives a Giant Egg. Fat Guys can also be used as platforms to cross obstacles such as spikes, as they are not damaged by jumping and Yoshi can safely stand on them.

When Yoshi has three giant eggs at his disposal, all of the Fat Guys will disappear until Yoshi uses at least one of the giant eggs.

Paper Mario
In Paper Mario, an individual Fat Guy named Gourmet Guy makes an appearance as a gatekeeping NPC during the events of the fourth chapter.

Yoshi Topsy-Turvy
Fat Guys reappear in Yoshi Topsy-Turvy, where they appear distinctly larger, being now roughly three times the size of Shy Guys instead of two.

Yoshi's Island DS
Fat Guys returns in Yoshi's Island DS, where they behave similarly to their first appearance.

Yoshi's New Island
While Fat Guys do not appear in Yoshi's New Island, a similar Shy Guy known as Mega Guy did.