Dark Fawful, Shadow Sovereign

Menace
When Dark Fawful enters the battlefield, you may sacrifice a creature. If you do, put four +1/+1 counters on Dark Fawful.
{b}{b}{b}: If "Bowser king of Koopa" is on the battlefield , sacrifice a creature, then transform "Bowser king of Koopa"
{u} : Target creature an opponent controls gets
-2/-0 until end of turn.
"Nnrrgh-GACK!"