Animal.io

Animal.io is sumo with farm animals. Everyone spawns on a shrinking platform, and the only goal is to push other players off the edge before they push you. Mouse movement steers your animal, and momentum cuts both ways: a charge is strong until someone sidesteps and your own speed carries you into the void. Food on the platform makes you bigger and harder to shove. Last animal standing wins the round. A match takes ninety seconds, which leaves room for revenge.