Thorn Crypt

Thorn Crypt enters the battlefield tapped.
At the beginning of your upkeep, flip a coin. If
you win the flip, Thorn Crypt deals 3 damage to
you. If you lose the flip, an opponent at random
rolls the chaos library.
{t}: Add {2} to your mana pool. Thorn Crypt
deals 2 damage to you.