Diablo, Dreaming Tyrant

Menace

•Whenever Diablo becomes tapped, each opponent mills three cards.
•Whenever Diablo is dealt damage, each opponent loses that much life and you draw that many cards.
•{2}{u}{b}: Untap Diablo. He gains indestructible until end of turn. Activate only once each turn.

"Disturb his rest, and the nightmare will not end until you do."