Geldoff was brought to Earth-616 by Dan Slott and Christos N. Gage in Avengers: The Initiative #8 (February 2008), where he was given the code name, Proton.

Geldoff is a Latverian orphan who was experimented on in the womb, gaining the ability to generate explosive orbs of energy.

After learning of Geldoff's origins, Professor Xavier plans to present him to scientific organizations and the United Nations as proof of illegal genetic research.

[2] Geldoff's Earth-616 counterpart first appeared in Avengers: The Initiative #8 (February 2008), and was created by Dan Slott and Christos Gage and artist Stefano Caselli.

This version is an Inhuman whose powers activated after Attilan was destroyed, releasing Terrigen Mist into Earth's atmosphere.