Click on the contestant you want to eliminate. Press space to switch between two teams, three teams, and the merge. Press the following keys to make a contestant rejoin/debut: Blocky: a Bubble: b Coiny: c David: d Eraser: e Firey: f Flower: g Golf Ball: h Ice Cube: i Leafy: j Match: k Needy (SLAP) Needle: l Pen: m Pencil: n Pin: o Rocky: p Snowball: q Spongy: r Teardrop: s Tennis Ball: t Woody: u The contestants can also be dragged!
Credit to ScratcherOfBFDI for the idea of the rejoining keys.