Skull

You summon an avatar of death--a ghostly
humanoid skeleton clad in a tattered black
robe and carrying a spectral scythe. It appears
in a space of the GM's choice within 10 feet
of you and attacks you, warning all others that
you must win the battle alone. The avatar fights
until you die or it drops to 0 hit points,
whereupon it disappears. If anyone tries to help
you, the helper summons its own avatar of death.
A creature slain by an avatar of death can't be
restored to life.