In his default appearance, Mimicstein appears as an amalgamation of various Earth fauna. He has a lizard-like upper body with some physical characteristics resembling a dolphin. He has blue and yellow skin, as well as a yellow beak. He has purple feathers on his wrists and yellow bird-like talons for hands. He wears a green belt and a black, green, and white uniform along his chest to his waist. He has a tiger-like lower body, with blue fur and black stripes. The front pair of legs being green reptilian and the back more feline. He has a black scorpion tail with a stinger.
The Omnitrix symbol is located on his chest.
- Enhanced Strength- Mimicstein is strong enough to lift a small car over his head.
- Enhanced Speed- Mimicstein can run at speeds up to 55 mph.
- Underwater Breathing- Mimicstein can breathe underwater using the gills on his neck.
- Sharp Tail- Mimicstein can use his scorpion-like tail as a sharp weapon.
- Power Mimicry- Mimicstein is able to mimic the powers of any other creature he can see. His body will morph in order to best utilize the gained abilities. (Examples: If he sees a Tetramand, he will bulk up with muscle and grow and an extra set of arms. If he sees a Lepidopterran, his eyes will grow stalks that he can shoot slime out of and large insect wings. If he sees a Petrosapien, his body will be covered in diamonds and he can grow and shoot diamonds at will.)
- Imperfect Mimicry- He cannot always perfectly mimic another alien’s powers. Aliens like Alien X or Way Big cannot be perfectly mimicked due to their godly powers or large size.
- Mimicry Limit- Any mimicked abilities will only last a few minutes if the mimicked alien is not in Mimicstein’s line of sight.
Before Primus disappeared, there was an error in the Codon Stream that spawned the Conglomersapiens, a mixture of unstable DNA that’s constantly changing. Azmuth discovered them living on Primus for a short time, and helped them migrate to the much more inhabitable Galvan M.
- Mimicstein’s prototype design resembled a mutation that Kevin Levin might go through, but it was changed to better fit the canon.
- Mimicstein’s current design was partially inspired by the alien race known as the Andalites from the Animorphs series of books.
- Mimicstein's species and their origin bare a strong similarity to that of Upgrade's species, as both were created by Azmuth, and both races alter and enhance their bodies through outside means.