Anti-Matter appears to be a skeleton-like being, emitting energy. He wears a containment suit, either to protect his form from dispersing into thin air or to protect others from the effects of his powers.
He introduced himself to a television audience, announcing his name and New York-based activities.
Note on appearance
The overall appearance of the character resembles the "Spooky Space Kook" (sic), a Scooby-Doo foe first depicted in a 1969 episode. The Kook is depicted as "a skeletal phantom-like creature with huge dull, and pale yellow eyes inside of a spacesuit".