Crystalfist is a Mutant Subsapian Hybrid and one of the Anitrix aliens in the 2016 Ben 10 series.
Crystalfist resembles a regular Petrosapien, with an inverted colors, being that his crystal-like body is purple. His clothing is also Black and purple.
Ben 10 (2016)
Crystalfist first appeared in the episode Franken-Fight, where Kevin Levin turned into him to fight against Ben Tennyson after noticing that he would not listen to anything he had to say. After seeing that Ben had a fear of tentacles, he later turned into Bootleg.
Crystalfist returned in the episode Heads of the Family, where Kevin turned into him to fight against the Tennyson family as well as Maurice and Sydney.
Crystalfist also appeared in the episode I Don't Like You, where Kevin turned into him to out preform Ben in a cooking show for the internet to see.
In the episode Roundabout: Part 2, Kevin turned into Crystalfist to fight against Forever Knight as well as to help both Ben and Gwen escape from a time vortex, only to be trapped himself.
In the episode Bottomless Ben, after fighting against Ben as Bashmouth, Kevin turned into Crystalfist to help both Ben and a park ranger fight against a rough minor. He possibly left a bit afterwards.
Crystalfist appears in a vision in the episode Tales from the Omnitrix, where Ben, Gwen and Max went to tell each other tales on how to defeat Kevin.
Crystalfist also appears in Ben 10 Versus the Universe: The Movie, where Kevin turned into him to fight against and escape from Vilgax.
In Ben 10: Power Trip, where Kevin would turn into him to help Ben fight against Hex and Lord Decible.