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
- Main article: Gourmet Guy
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 the Game Boy Advance game, Yoshi Topsy-Turvy where they once again appear as enemies and try to defeat Yoshi.
 Yoshi's Island DS
Fat Guys returns in Yoshi's Island DS, where they behave similarly to their first appearance.
 Notable Fat Guys
 Names in other Languages
|From Debu (fat, chubby) and Heiho (Shy Guy's Japanese name)
- In Mario Party DS, Fat Guy has a cameo on the Soda Cup and Fries in the minigame Fast Food Frenzy.
- When a Fat Guy walks, its left foot tends to disconnect from the rest of his body on the back-step.