Darth Vader, The Chosen

Menace, Death Touch, First Strike
{2}{b/r}: Darth Vader, The Chosen deals 3
damage to any target and you lose 1 life.
At the beginning of combat, you may sacrifice a creature, adding X to Darth Vader,
The Chosen's power and toughness until
the next end step where X is the sacrificed
creature's power.