Acid Breath has wrinkly, pale skin. He has red eyes with different-sized pupils, and little bits of straight black hair poking out of the top of his head. Most of his teeth are missing and his gums are green.
His outfit is black with bright yellow stripes on his arms and he has a little bit of a hunch back.
In Omniverse, Acid Breath looks much younger than the original series. He looks paler, the hair on his head has curled, and he has a more greenish skin tone. His eyes are now the same. His outfit looks similar to his original one, but his shirt goes all the way to his neck and it has a more overall-like appearance.
Acid Breath first appeared in Last Laugh. He was performing in a circus to attract an audience and later went out to rob while Zombozo fed on the laughter of the town. He and the other freaks were stopped by Wildmutt, but saved by Zombozo. During Upgrade's attack later on, Acid Breath's mouth was plugged by a baseball, following Upgrade merging with a baseball launcher.
In Ghostfreaked Out, Acid Breath and the rest of the Circus Freaks were robbing a school, until they were stopped by Zs'Skayr, who later forced them to work for him. He later battled Four Arms and failed to capture Grey Matter. When Zs'Skayr sent the Circus Freaks after Max and Gwen, Acid Breath cornered Gwen in a kitchen. Gwen managed to neutralize his spitting with a fire extinguisher, then hit him on the head with a frying pan, knocking him out.
In Ben 10 vs. the Negative 10, Acid Breath, Thumbskull and Frightwig were part of the Negative 10. Acid Breath attempted to wrest control of the group from the Forever King early on, but he and the rest of the Freaks were beat back by the Forever Ninja.
Acid Breath appeared in Something Zombozo This Way Comes when he and his team were re-hired by Zombozo to distract Ben while he is feeding off people's fear. He was defeated when Frankenstrike shoved Frightwig's hair in his mouth. Zombozo used his breath to light a cannon to escape and then threw him aside. After Zombozo escaped, Acid Breath and his team were arrested by the Plumbers.
Powers and AbilitiesAcid Breath can release corrosive acid from his mouth in the form of either a vapor or a liquid; he claims that he learned this from his mother. This acid can easily dissolve whatever he wants it to, even metal and stone.
Acid Breath is also quite agile.
If his mouth is jammed by an object (such as a baseball) or if something causes him to cough and gag (such as the contents of a fire extinguisher), Acid Breath will be briefly unable to use his acid breath or spit.
- Last Laugh (first appearance)
- Ghostfreaked Out
- Ben 10 vs. the Negative 10: Part 1
- Ben 10 vs. the Negative 10: Part 2
Ben 10: Omniverse
- Something Zombozo This Way Comes (first re-appearance)