Menacing Vampire

Menace, Lifelink, Haste
Whenever a creature is dealt damage by Menacing Vampire, that creature's controller sacrifices it at end of combat.
Whenever Menacing Vampire deals combat damage to a player, create a Blood token.
{6}{u}{b}{r}, Sacrifice 3 Blood tokens: Convert Menacing Vampire. Activate only if a creature has been sacrificed this turn with Menacing Vampire.