What it does
Craft is an activated ability found on certain transforming artifacts and creatures. By paying a cost—usually mana plus exiling other cards (from your graveyard, battlefield, or even cards exiled by that permanent)—you transform the card into its more powerful back face. It can only be activated as a sorcery (your main phase, empty stack).
The big nuance: crafting works like an activated ability, so the permanent leaves and re-enters as a transform, but it's the same permanent—it doesn't trigger "enters the battlefield" effects, and it stays summoning-sick if it was. Also, exiling permanents you control with craft means they leave the battlefield, which can trigger death-like effects or lose you board presence, so weigh the cost carefully.
In Commander, craft rewards graveyard-heavy or token decks that can cheaply feed it. Since the back faces are typically strong, it offers a slow-but-inevitable value engine that's hard to interact with once online.













