Gollum

Trahald, aka Sméagol or Gollum is a mad Hobbit ruined by the One Ring. He murdered his best friend for it, although he told himself it was his birthday present. When the Ring left him, he chased "that nassssty Bagginses", (Bilbo's) first cousin once removed, Frodo, to the very Cracks of Doom, where Gollum and Ring fell into the lava.