Sebastian, Golgari Witch-king

When Sebastian, Golgari Witch-king enters the battlefield put a curse counter on every nonland permanent your opponent controls.
At the beginning of your next upkeep,
destroy every card with a curse counter on it.
{b}{g}{t}: Sacrifice Sebastian, Golgari Witch-king
and search your libary for a multicolored creature
or planeswalker und put in into your hand, then shuffle your libary.