Sleipnir, Odin's Steed

Sleipnir enters the battlefield with six +1/+1
counters on it. It escapes with twelve +1/+1
counters on it instead.
If damage would be dealt to Polukranos while it
has a +1/+1 counter on it, prevent that
damage and remove that many +1/+1 counters
from it.
{1}{b}{g}: Polukranos fights another target creature.
Escape-{4}{b}{g}, Exile six other cards from your graveyard.