PrototypePrototype is a static ability that appears on prototype cards that have a secondary set of power, toughness, and mana cost characteristics. A player who casts a spell with prototype can choose to cast that card “prototyped.” If they do, the alternative set of its power, toughness, and mana cost characteristics are used. See 718, “Prototype Cards.” (CR 702.160) — 2/5 (You may
castTo cast a spell is to take it from the zone it’s in (usually the hand), put it on the stack, and pay its costs, so that it will eventually resolve and have its effect. A player may cast a spell if they have priority. See rule 601, “Casting Spells.”
To cast a card is to cast it as a spell. (CR 701.5) this spell with different mana cost, color, and size. It keeps its abilities and types.)
Whenever this creature attacks, target attacking creature gets +X/+0 until end of turn, where X is this creature's power.