The Great Worum

When The Great Worum enters the battlefield, reveal the top X cards of your library. An opponent separates those cards into two piles. Put one pile in your graveyard and the other on the top or bottom of your library.
Your opponents cannot cast spells that share a type with the top card of your graveyard.
It's lair is an island of bones, ever growing, in the centre of the most putrid bog.