Historical Rules · 18 November 2022
Rule 719.3c
Official source text from the 18 November 2022 Rules release
If a prototyped spell is copied, the copy is also a prototyped spell. It has the alternative power, toughness, and mana cost characteristics of the spell and not the normal power, toughness, and mana cost characteristics of the card that represents the prototyped spell. Any rule or effect that refers to a prototyped spell refers to the copy as well.