Surma is a beast similar to Cerberus in the Finnish mythology of Kalevala.
Surma also means kill, or specifically a kill and the verb surmata, to kill or to slay, is derived from it.
Surma is often described as being a large dog with a snake-tail and can turn you into stone (with a stare).
Surma is a terrible beast that guards the gates of the Underworld or Tuonela to prevent escape. An often-used Finnish metaphor is surman suuhun "into Surma's mouth", as if the victim was mauled to death by Surma.