agario is a massively multiplayer action game developed by Matheus Valadares. agario game a multiplayer browser game in which players have to eat competitors or be eaten while striving to dominate the world of colorful cells. agario skins can be played in a deathmatch or between teams. To control the game agar.io you just need to use your mouse/track pad, the "w" key and the SPACEBAR. The mouse navigates your blob around and the SPACEBAR allows you to split your cell(s) in half and the "w" key allows you to eject mass for feeding other players, viruses or help you drop some weight to get out of a tough spot. Enjoy the world of agario skin!