OnionHead is a small Onion-Like alien. He has three crab-like feet on either side and behind his body, and large stalks sprouting from the top of his head. He wears a black suit on his mouth with green and white details.
The Omnitrix symbol is located on his face.
- Enhanced Intelligence- OnionHead possesses a high intellect that allows him to understand, create and operate advanced technology.
- Noxious Spores- OnionHead is able to emit spores from his mouth that when inhaled cause an intense burning sensation on the eyes, mouth and nose, eye-watering, and blurred vision. If high quantities of spores are released at a time, they can generate a smokescreen effect.
- Sprout Overgrowth- OnionHead can manipulate the stalks located on top of his head, being able to move and increase them in size at will.
- Speech Incapability- Onionhead's language is unable to be translated, creating a communication disadvantage with other life forms.
- Physical Limitations- Onionhead's simple limbs lack any fine motor skills for their lack of digits, significantly impairing him from reaching his full potential in machinery building.
Nogrog was visited by the Eradicators; and, deemed to be a threat to the Kryptonian hierarchy, was promptly attacked.
- OnionHead shares a home planet with Callus, however the two species are unable to communicate due to a language barrier.
- A Sanavox is able to translate OnionHead's language, but because of the advanced vocabulary he uses, they would not understand what he is talking about most of the time.