Dungeon Master

Indestructible
Dungeon Master isn't a creature unless you
have {w}{u}{b}{r}{g} among mana costs of
permanents you control.

Once per turn during your Pre-combat Main
Phase, you may search the top {x} cards of your
library for a creature or equipment card, where {x} is the number of floating colored mana you
control. Put that card into your hand and return
the others to your library, then shuffle.