Calaveras, the Cunning Whip

Vigilance

When Calaveras comes into the battlefield, you can choose an opponent. At the beginning of that player's upkeep, that player sacrifices a creature, and you gain life equal to its toughness.

Whenever a creature you control enters the battlefield or dies, you gain life equal to its power.

"Loyalty is a chain, but even chains can be broken with a swipe of a whip."