Chaos 6

Chaos 6 (カオス 6) is a transformation that appears in the anime series Sonic X. It is the form attained by Chaos after absorbing the negative chaos energy of six Chaos Emeralds.

Appearance
Chaos 6 is dramatically from any of Chaos' previous forms. It is no longer humanoid, instead vaguely resembling a bloated scorpion/frog-like creature. Over three times Big's height, it has a massive body with two extensions/antennas on its sides, two pair of digit-less legs, and a similar pair of large hind legs bending backwards. It has as well a large mouth with sharp teeth and two large eyes aligned vertically on its face with three smaller eyes aligned horizontally on each side. It also has a zigzagged tail with a blunt tip. Running through its hind legs are grey bones, connected in the rear by a pelvis-like bone, with a Chaos Emerald embedded in each of them. In its belly lies it brain, encircled by four standing bones, each with a Chaos Emerald on top.

Chaos Saga
Chaos became Chaos 6 when Dr. Eggman fed Chaos 4 two more Chaos Emeralds onboard the Egg Carrier. As Eggman gave Froggy to Chaos 6 so it could get its tail back which Froggy had drunk, Chaos 6 swallowed the frog, along with as Chris and Big when they tried to save Froggy, restoring its tail. Though Sonic attempted to rescue his friends, Chaos 6 pinned him down. However, Knuckles came to the rescue and the duo came up with a plan. With Knuckles using the Shovel Claws to expose Chaos 6's brain, Sonic defeated Chaos 6, causing it to revert back to Chaos 0 and relinquish its Chaos Emeralds.

Powers and abilities
Having absorbed six Chaos Emeralds, Chaos 6 is even more powerful than Chaos 4. In this state, Chaos' defensive capabilities have drastically increased as its skin can now withstand any form of blunt attack, although it can still be pierced by sharp objects.

Being made of liquid chaos energy, Chaos 6 can mimic the properties of water. This gives Chaos 6 a limited degree of shapeshifting, such as sprouting powerful tentacles to strike its foes with. As its body changes, it becomes as well more powerful. Combined with its water-like composition, Chaos 6 can even absorb blunt impacts and eject those that have embed themselves in it with surprising force.

Weakness
Chaos 6's weak spot is the brain in its belly. If exposed and attacked, it causes Chaos 6 significant damage.