Lost spirits may appear when skilling in the surface world during the 2015 Hallowe'en event. Collecting one gives half the experience provided by a regular jack of trades aura's reward book in any skill. It should then be returned to Sinn Derkwill in the Underworld for 100 Noumenon Favour. Only two lost spirits will appear for a player per day. When the first spirit appears, this message is shown: A lost spirit has appeared nearby! The second one arrives with the message: A lost spirit has appeared nearby, you feel like it'll be the last to appear for you today... Unlike Mysterious meteorites, Lost spirits that appear to other players cannot be claimed.