Since you bring that up:
-You should be able to Double Megamerge with any two Biometals...
Then you would have multiple versions of Pandora.
Besides it should only belong to X since he had the DNA weapon system first that, in my theory, would be X's secondary effect like the things you can do on the touch screen with the Big4's biometals, Model A's A-Trans, and Model W's ability to control people, eat people, and revive Mavericks. If Model Z had a secondary effect I would say it would be the EX skills.
But you know what's bugging me about ZXA lately, whatever the heck Model Z did to the Small4. Does it remind anyone else of the Soul Body attack in X5 in the X vs Zero or just me? Anyway this is just speculation.
That would Rock actually. Ive always wanted to play as Model Z alone. Although whether Vent or Giro uses it is of no consequence to me.
Vent can't possibly do that, he can't be chosen for 2 biometals.