Geldoff was a Latverian orphan, he was adopted by an American couple and moved to New York, and studied at Queens. While at a party at his house, where Peter Parker was, Geldoff showed his powers to his guest by blowing up random cars. Then the police appeared and everyone left the scene. Next day he started blowing up cars again, but this time Spider-Man appeared to face him and make noticing him of his irresponsible behavior. The police appeared and while Spider-Man was swinging away, Geldoff grabbed onto Spidey's clothes.
At a rooftop, Spider-Man tried to convince him to use his abilities to help people, but Geldoff couldn't see why. At the moment some robbers who where in a shop were being defeated by Spider-Man, Geldoff used his powers to explode a car, which injured not only the robbers, also innocents. Geldoff believed he done something good, but a Spider-Man enraged hit him and explained him that he must be more cautious to use his powers, he could have killed people. Geldoff angrily threatened to use his powers directly on the hero, but was interrupted by the arrival of the X-Men, Marvel Girl, Storm and Kitty Pryde. When they explained him he's actually a mutant, thing he hates, Geldoff fainted. Spider-Man was explaining to them about the situation when Geldoff woke up, but fainted again.
Professor X suggested telepathically to take him to his school. While at the plane, Geldoff woke up, and frightened blew out the side of the plane. Storm managed to extinguish the fire and get her partners back to the plane, except Spidey and Geldoff, who were knocked out at the explosion but were rescued by Jean Grey just in time. Later, at the mansion, with everyone safe, Professor X telepathically sedated Geldoff and managed to determine his experimental origins. Xavier decided that the best thing to do is to present Geldoff to the scientific organizations and the United Nations as proof of immoral and illegal genetic research. Geldoff apologized to Spider-Man and the hero was taken back to Queens by the team.
Geldoff can generate and discharge explosive energy balls. How this power affects living tissue is unknown, as he has yet to use it on anything organic; Geldoff himself seems immune to the energy. His ability worked through his thoughts and focus, he only needed to focus his thoughts towards an object and then it would explode.
- 6 appearance(s) of Geldoff (Earth-1610)
- 1 appearance(s) in handbook(s) of Geldoff (Earth-1610)
- 3 image(s) of Geldoff (Earth-1610)