Corner

Until the end of your next turn, whenever an opponent casts a spell, or a creature an opponent controls attacks you, that player loses 3 life.
At the beginning of your upkeep, if an opponent hasn't lost life since the end of your last turn, return Corner from your graveyard to your hand.
"Teysa won't be coming to you rescue. This ends your time as the Guildpact." -Karlov of the Ghost Council