Mentacle resembles a reptilian humanoid with a prehensile tail and three tentacles sprouting from their head as well as three eyes relative to each tentacle. He wears a green, black, and white uniform.
The Omnitrix symbol is located on his chest.
- Telekinesis- Mentacle has telekinetic abilities allowing him to move objects with his minds.
- Flight- Mentacle can use telekinesis to fly.
- Prehensile Tail- Mentacle's tail can be used to grab onto things.
- Prehensile Tongue- Mentacle has a long, forked tongue that he can use pick up small objects and go for the eyes and other soft organs, in a last ditch effort.
- Three Brains- The trio of brains Mentacle has gives him good reflexes and heightened mental prowess.
- Sharp Claws- Mentacle has sharp claws that can easily cut through glass.
- In Chapter 10: Again (Page 2), Mentacle is seen alongside several other transformations, making a cameo appearance during Danny's opening monologue.
- Chapter 10: Again (cameo)
- Mentacle is the same species as Max's old flame, Xylene.
- The Uxorite species was given sexual dimorphism for this alien: The female Xylene has two longer head tail to Mentacle's three shorter ones.
- Alternate names voted on for Mentacle's eventual designation include Brain Blast and Liftoff.