Kraxos, Roil's Tide

Hexproof from colorless
Whenever Kraxos, Roil's Tide deals combat damage to a player, target creature that player controls gets -1/-1 until end of turn for each Island you control.
Kraxos watched helplessly as Kozilek sundered Lorthos in two. A simmering vengeance kindled in his inky heart, fueled by the trauma of his father's death.