Gaea's Cathedral

Covenant — Each nonland card in your starting
deck is green and/or is an artifact. (If this card is
your chosen covenant, you may begin the game
with it in your hand.)

Cumulative upkeep: Discard a card

You cannot play spells, draw cards, gain life, take damage, or lose life. You cannot lose the game.

Sacrifice this card: Regenerate target creature