In Laaaava.io you compete with four other players at a time. All of you are balls of various colors about to be consumed by a pool of lava underneath you. But not all is lost: you can click your left mouse button to jump and prolong your life. Other players will do that to and also they'll try to push you to your death, because only the last surviving ball wins.
Laaaava.io is a fast and fun game that doesn't take a lot of time and effort - give it a shot.