Origin

Harpoon was one of the mutants who attacked Angel in the Morlocks tunnels. He pinned angel to a wall with his harpoons which resulted in Angels amputation of his wings. Thorsaved Angel before Harpoon could finish the job. He was also responsible for attacking Kitty Pryde which left her in a ghost like state. Harpoon also hurled a harpoon at a vulnerable Rogue who had her powers "scrambled" by Scrambler. Kitty grabbed Rogue hoping the harpoon would phase through them but ti still hit them because it may have been in its energy state. He was thought to have been slain during Inferno but it appears that Mr. Sinister's cloning abilities makes it so that he never really "dies".

Harpoon was shown to be one of the many mutants to lose their powers after M-Day. He still is a member of the Marauders.

Powers

Create energy lances which could be used for various purposes. He also has the ability to replenish his weapons like Riptide.

Now depowered, he still fights using energy spears, presumably powered by other means than his mutant power.