sans, the final judge

+4: summon gaster blaster. it has 5/infinite, it dies after one turn, it inflicts karma with 1 damage every turn. karma lasts for 5 turns.
-1: prevent all damage to this planeswalker.
0: sans does 5 damage and inflicts karma. what karma does is that it inflicts karma with 1 damage every turn. karma lasts for 5 turns.