What is the IO game where you eat other animals?

Excuse me, could you elaborate on the "IO game" you're referring to? Are you talking about a specific online multiplayer game where players control small animals or creatures and the objective is to consume or defeat other players' creatures in order to grow in size or power? If so, there are several popular titles that fit this description, such as Agar.io, Slither.io, and Diep.io, among others. Do any of these sound like the game you're thinking of?