Samael, Cunning Prosecutor

Whenever Samael, Cunning Prosecutor enters
the battlefield exile the top card of an opponents library.
Every time any player casts a instant or sorcery
spell, that player looses 2 life and discards a card.
Any time a player casts a nonland spell, you
may pay {u}{b} and exile a creature from your graveyard. If you do, counter that spell and
draw a card.