A hero in the DC Animated Universe (Earth-12).
While he was training at JLU HQ he got a call to stop a runaway monorail. When he got there he immediately saved the driver and went back to veer the machine somewhere safe; he finished but when he tried to escape a forcefield held him in and he went down with the monorail. He was temporarily replaced by Terry McGinnis. Later, Micron managed to save Terry from a Superman possessed by Starro.
He later invites Terry once again to join JLU. Terry once again says no.
However, following the events of Hush Beyond, it is possible that Terry may reconsider the offer.
Micron's history is explored more in the comics. It is revealed that he had his powers since birth, resulting in abnormal growth. He eventually learned to control it as a teenager. It was this, along with Superman vouching for him, that allowed him to become a member of the Justice League.