In this game, you start out as a small creature—typically a fish or something aquatic, since underwater environments seem to lend themselves to this kind of gameplay. There are many other creatures around you: some are smaller than you, some are bigger than you. If you touch one bigger than you, you are eaten, and die. If you touch one smaller than you, they are eaten, and they die — but you get slightly bigger. This allows you to eat slightly bigger creatures than you previously could. There may be a maximum size to reach to win, or maybe it goes on forever. Maybe you reach the biggest size, ending all difficulty, and the game doesn't end, because it's hard to get there and they didn't think to program an ending. They often count your score: it's a classic style of arcade game. Because it's really simple to make, play, and understand, this type of game existed on a lot of early video game platforms, including consoles, plug-and-play games and arcade games. The first one of this type is not currently known with certainty. Multiplayer variants have risen in popularity since Agar.io .
- Agar.io and Slither.io (multiplayer) are multiplayer games of this type — in Agar.io you control blobs/amoebas and in Slither.io you control snakes. They are available online in the browser and have some power-ups as well (splitting your amoeba on demand for example).
- Mope.io takes this more literally by using animals.
- Osmos with plenty of passive targets, but a branch has opponents that are active players.
- Odell Down Under for DOS.
- Shark! Shark! on the Intellivision. Possibly the Trope Maker.
- Fishie Fishie by farbs.org.
- Feeding Frenzy series by Pop Cap.
- Katamari Damacy — the objects that you're aggregating do not fight back, and you win at a certain maximum size.
- Tasty Planet
- Spore, at the cell stage.
- flOw, by ThatGameCompany for PS3, also a Flash game: You start as what is apparently a fish, that eats things, to become bigger fish which help you eat the eat fish that tried / try to eat you.
- Fishy! at fishy-flash-game.com, by XGen Studios.
- The Flash game Bobulous has you eat smaller enemies (and avoid larger ones, of course) that are Color-Coded for Your Convenience. Features growing in size after each level.
- The Visitor Flash game series involves an alien slug that eats animals and gains their form and abilities, with the ultimate goal of eating a human.
- Hungry Space is a space monster version. The space creatures even resemble fish.