Wooloo, Deathbringer

When Wooloo, Deathbringer enters the
battlefield deal 20 damage to all opponents.
{b}{g}{b/g}: Deal 10 damage to all of target player's creatures.
{10}{b/g}{b/g}: Destroy all creatures with toughness
under 10
{x}{b/g}: Wooloo, Deathbringer gets +X/+X
{4}{b/g}{b/g}: Create a 5/5 Sheep token with {t}:
Target player gains 5 life