Chaos 4 is a transformation that appears in the Sonic the Hedgehog comic series and its spin-offs published by Archie Comics. It is the form Chaos takes upon harnessing enough negative Chaos energy to equal about four Super Emeralds.
Chaos 4 is similar to a shark, with a dorsal fin on both its back and a horn on its forehead, and the flaps on the sides on its head have grown longer. It also has two sharp pelvis fins and a pair arms.
While in the Mystic Ruins, Dr. Eggman fed Chaos 2 two additional Super Emeralds that Tails accidentally dropped while running, transforming Chaos 2 into Chaos 4. The beast then did battle against Sonic, Knuckles and Tails, but was defeated, so Eggman tried a new plan with the Egg Carrier.