Rootwire Amalgam

Regardless of how it was cast, a prototype card always has the same name, abilities, types, and so on. Only the mana cost, mana value, color, power, and toughness change depending on whether the card was cast as a prototyped spell.

A prototype card is a colorless card in every zone except the stack or the battlefield, as well as while on the stack or the battlefield if not cast as a prototyped spell. Ignore its alternative characteristics in those cases. For example, while it's in your graveyard, Blitz Automaton is a colorless creature card with mana value 7. It can't be the target of Recommission, a spell that targets an artifact or creature card with mana value 3 or less in your graveyard.

Use Rootwire Amalgam's power as it existed the last time it was on the battlefield (not the power of the creature card in the graveyard) to determine the value of X.