What Happened To Everyone Who Joined The Weapon X Program?

Team X was the field op team created by the CIA, who also created the Weapon X Program. Team X's job was to basically handle anything that would get in the way of Weapon X being their evil selves. But don't think that made the members of Team X immune to Weapon X's treachery.

Just look at poor Mastodon, who - like his more famous teammates - had memories implanted in his brain to make him more trusting of his bosses. Mastodon had an age-suppression factor that was given to him by Weapon X, while his combat skills were found in firearms.

His story is the shortest and most tragic of all, as when we meet him in the then present day, Wolverine finds Mastodon's age-suppressor has reversed. Mastodon dies in Jubilee's arms, aged into oblivion.