Snowman spy

When snowman spy attacks put ten +1/+1 counters on him
Every upkeep double his +1/+1 counters on him
Can't be countered
Annihilator 10
Hexproof
When Snowman spy enters the battlefield
Put five +1/+1 counters on him
Snowmen spy's power and toughness are equal to the number of +1/+1 counters on him