Beowulf, Betrayed Son

Trample, First Strike, Vigilance
Whenever Beowulf, Betrayed Son deals combat damage to a player, put 1 Moon counter on him.

Creatures your opponents control have -X/-X where X is the number of Moon counters on Beowulf.
"They say only great men can be monsters! Are
you a great man, Beowulf!?" - Haken