Gulor, Vampire Night Stalker

Haste
Flying, menace, deathtouch, lifelink
Whenever an opponent is dealt damage by Gulor,
Vampire Night Stalker, you may pay {1}{b}. If you
do, you may have that player sacrifice a creature
or discard a card (you choose).
The night is young, its mildness sickening, its
seductions subtle and treacherous.