Metal Slug is a run and gun video game series created by SNK. It focuses on the adventures of Peregrine Falcon Squad, a crack team of commandos who battle aliens, dictators, and other factions bent on world domination.

Fitting in with the series' cartoony bent, eating 16 pieces of food causes your character to spontaneously gain weight. Power is increased while speed is greatly lowered, and humorous changes are made to the character's animations, including using a fork instead of a knife as a melee weapon. The transformation wears off eventually on its own, but can be cured quicker with a diet pill or barrel of diet formula.

Metal Slug 2/X

This is the first Metal Slug game when the character gets fat, in the normal version the fat appears on mission 4 while in the MSX version the character gets fat from missions 3 to the rest of the game's missions.

Metal Slug 3

The fat reappears in this game, the player could get fat on missions 1, 4 and final mission.

Also, barely noticable, appearing only for literal fractions of seconds are enemy inflations - some of the mutant enemies expand. The small maggots inflate when killed before bursting, and so do the flying piranha.

Metal Slug 4

Once again the fat reappears but only on mission 3, also in the end of the game, if you get escape from Amadeus's secret base explosion, you'll get the Good Ending on where Marco, Fio, Trevor and Nadia overeats in a buffet getting an obvious result.

Metal Slug 5

The fat reappears for the last time in the official series only on mission 1

Metal Slug 3 Pachinko

Fio eats a lot of food leading to her getting fat as a result

Metal Slug Defense

The fat reappears with Fat Marco, Fat Eri, Fat Tarma and Fat Fio in this game for Android/IOS, to get them you must rescue all the P.o.W.s from the Alternative World beating the bosses from Monday, Tuesday, Wednesday and Thursday

Metal Slug Attack

Two Extra OPS called Food Army and Food Army 2nd gives as the main units the fat versions of the Main Heroes.

  • Food Army gives Fat Marco and Fat Tarma from November 17, 2016 to November 20, 2016
  • Food Army 2nd gives Fat Eri and Fat Fio from January 20, 2017 to January 23, 2017

Actually they can be obtained on Mars Shop mode since MSA's 2.13.0 update.

An upgraded version of Fat Eri called Special Fat Eri has been added on 2.21.0 update as part of the Expert Units for the Extra OPS "Hero of Justice".

She can actually be obtained via Mystery Crank.

Also, an upgraded version of Fat Tarma called Special Fat Tarma has been added on 3.0.0 update as part of the Expert Units for the Extra OPS "United Front the 3rd".

He can actually be obtained via Mystery Crank.

Neo Geo Battle Coliseum

In this Crossover game between SNK and its cousin company ADK, Marco and Mars People faces Metal Slug Franchise, one of Marco's moveset is called Breakfast which is clearly a reference to the Fat Form and its effect is to make Marco recover some health in battle.