How to meet Wisp
Wisp is a special spirit character who appears in Animal Crossing: New Horizons in the early hours of the morning, that is, between 8:00 pm and 4:00 am.
Every time you interact with him, he'll lose all his wits because you've scared him. He'll ask you to retrieve his 5 spirits in exchange for a reward.
How do you get Wisp's spirits back?
Simply spot blue lights floating all over your island. Simply use your net to catch them.
What to do once the 5 spirits have been caught?
Return to Wisp and give him his 5 spirits. As a reward, he'll ask you to choose an expensive item (worth 10,000 bells or less) as a reward, or an item you don't currently own (worth 1,500 bells or less, or an item not in the catalog).
Wisp will always tell you whether the item he's offering is clothing, furniture, flooring or wallpaper. Unfortunately, since Wisp doesn't understand the value of objects, your choice of expensive item doesn't guarantee a valuable reward, and vice versa. Once the reward has been given, Wisp will disappear and can be found again in the early hours of the following day.
Nook Miles rewards
By helping Wisp, you can unlock Nook Miles rewards. You'll receive Nook Miles rewards the first, 10th and 20th time you help Wisp.