Gudbad, Violent Collector

Eminence - You may spend mana as though it were mana of any type to cast spells and activate abilities of sources you control but don't own.

Whenevr you play a land or cast a spell you don't own, you may pay {u/b}{b/r}. If you do, exile the top card of target opponent's library. You may play that card for as long as it remains exiled.

At the beginning of your upkeep, Gudbad deals damage to each opponent equal to the number of permanents you control that that player owns.