Chaos

Chaos is a water-like creature that appears in the Sonic the Hedgehog franchise. He is known for his ability to change form every time he gets a Chaos Emerald, eventually turning into Perfect Chaos when he has all seven.

Super Smash Bros. Brawl
In Super Smash Bros. Brawl, Chaos makes a cameo as a sticker.

Super Smash Bros. Ultimate
Chaos appears in Super Smash Bros. Ultimate as a primary, Advanced-level spirit.

Mario & Sonic at the Olympic Winter Games
Chaos makes two minor appearances in the Wii version of Mario & Sonic at the Olympic Winter Games. One is as a frozen version of his Perfect Chaos form, which appears in the Sonic World version Dream Figure Skating as an obstacle and needs to be defeated by jumping into him. He also appears as a VIP member that gives the player 100 Star Points when spotted.