Mister Fantastic
During the 2015 "Secret Wars" storyline, the nearly omnipotent Doctor Doom kept Molecule Man in a special chamber in his castle following the formation of his Battleworld. During the attack on Castle Doom, the two Spider-Men (Peter Parker and Miles Morales) found the chamber that Molecule Man is in. Like every visitor before him, Molecule Man asks if they had any food with them. Miles gives him a hamburger from his pocket, for which Molecule Man states he is in debt to Miles. Upon learning that Molecule Man is the source of Doom's powers, the two Spider-Men leave. Mister Fantastic and Maker (the Earth-1610 version of Mister Fantastic) enter Molecule Man's chamber where Maker is seemingly killed by Molecule Man while Mister Fantastic fights God Emperor Doom. To make the fight between Mister Fantastic and Doctor Doom fair, Molecule Man depowered Doom. During the fight, Doom admits that Mister Fantastic would have done better with the godlike powers, and in response, Molecule Man gives his powers to Mister Fantastic, causing Battleworld to fall apart. Using Molecule Man's powers in conjunction with Franklin Richards' ability to conjure entire universes, Mister Fantastic begins to reconstruct the Multiverse. As each new reality is recreated, a portion of Molecule Man attached to it as an "anchor", which has the effect of restoring his sanity. In gratitude to Miles, Molecule Man transfers him, his family (including his now-resurrected mother), and his friends to Earth-616, now known as The Prime Earth. Their entire life histories are merged with this new Prime Earth, and have no memory of having originated from a different universe, except the participants of the Battleworld who still have their former respective original universes' memories intact.