Dio Duck

Dio Duck is a secret boss in snowdin. He can be found near the Snowdin entrance/hallway and there will be an invisible teleporter on the left wall. He requires 110+ levels to enter. He drops the Soul Scythe which can create a zone-like attack which is square and flashing the colors of the rainbow. The Soul Scythe also flashes the colors of the rainbow, but does not emit light. It is a good weapon for beginners.