Complete Genocide

When any creature under your control kills an opponent's creature, add 1 Genocide counter to
this card. All of the creatures under your control
gain the following effects (effects stack):
1. Creature gains +1/+0
2. Creature gains +1/+1
3. Creature gains +2/+1 and Menace
4. Creature gains +2/+2
5. Creature gains +3/+3 and Vigilance
10. Creature gains +5/+5, Trample and Doublestrike