

In The Forge of Creation, 10-year-old Heatblast's appearance is a mix between the Ultimate Alien design and the Original Series' body color. In Heroes United, Heatblast looked the exact same as he did in the Original Series, only his jaw was a lot lower than it was before. The rocks over his body changed, with a burnt black color and red markings on every edge of his rocky skin, resembling charcoal and his plasma body is a lighter shade of yellow. His eyes were no longer connected to the fire on his head. In Ultimate Alien, Heatblast closely resembled Alan, only taller, not as skinny, slightly altered and his face shape was more similar to the Original Series. The Omnitrix symbol appeared to be embedded in his chest. His stone skin gained cracks of yellow glow and his plates were further apart, exposing almost parts of his plasma body. In Race Against Time, Heatblast had less fire on his head and most of his head was exposed. The rocks show small but noticeable cracks around him, much like other minerals.

In Destroy All Aliens, Heatblast looks the same as he did in the Original Series, except his plasma body glows brighter, and emits movement, similar to the Sun. In Back with a Vengeance, Heatblast wore a yellow raincoat.Ĥ-year-old Heatblast looked the same as 10-year-old Heatblast did in the Original Series, but with a much smaller and thinner body, as well as an oversized head. When under the effects of a cold in Side Effects, Heatblast's fiery skin (excluding his rocky body) turned blue. His tongue is also made of fire while his collarbone resembles a volcano which generates a fiery "hair" that covers his head, leaving his mask-like face visible with no nose or ears. His feet have a slight oval-like design with only two toes and one back toe. As a fire-based entity, his body radiates high amounts of heat.

Heatblast is a plasma-based life-form whose body is composed of a super hot inner plasma body covered by dark reddish brown volcanic rocks.
