"PU does! create a second one. But the second one uses its passive cause it's coming into play, and therefore absorbs previous one (and i believe any other creature you have)."
no, if PU made a second one, it would make copy of the 6|10 creature, then combine it with the other chimera to make it a 12|20 creature, but iirc it just flashes in/out of existence. it is a spell pretending to be a creature.