In Norse mythology, Sköll (Old Norse "Treachery") is a warg that chases the horses Árvakr and Alsviðr, that drag the chariot which contains the sun (Sól) through the sky every day, trying to eat her. Sköll has a brother, Hati, who chases Máni, the moon. At Ragnarök, both Sköll and Hati will succeed in their quests.
Sköll, in certain circumstances, is used as a heiti to refer indirectly to the father (Fenrir) and not the son. This ambiguity works in the other direction also, for example in Vafþrúðnismál, where confusion exists in stanza 46 where Fenrir is given the sun-chasing attributes of his son Sköll. This can mostly be accounted for by the use of Hróðvitnir and Hróðvitnisson to refer to both Fenrir and his sons.