Gollum, Obsessed Stalker

Legendary Creature — Halfling Horror

Skulk (This creature can't be blocked by creatures with greater power.) At the beginning of your end step, each opponent dealt combat damage this game by a creature named Gollum, Obsessed Stalker loses life equal to the amount of life you gained this turn.

He hated the Ring and loved it, as he hated and loved himself.