Millennian

You may have this creature enter as a copy of a
creature an opponent controls, except it isn't
legendary and it has "Other creatures of the same
name get -1/-3."

———{line}{line}{line}{line}{line}
The Millennians within took on a giant
collective form. However, the Organizer G1 present in
Godzilla's cells had an unanticipated side effect,
causing the Millennian to spontaneously mutate.