Harley is a castaway on the island The Hamlet.
A message in a bottle is found on the southern side of the second island of the Islands That Once Were Turtles, which can be investigated to receive a treasure map.
The message in a bottle to locate this castaway is currently visible. (wrong?) Once a message in a bottle is found and when a player has walked near its spawn location when it was visible it will always be visible, unless the message in the bottle or its treasure map is in the player's bank or inventory.
On the island, players can talk to Harley, a cyclops skull with a terrible headache. He wanted headache medicine, which the player didn't bring. When spoken to, Harley will give the player one taijitu in thanks for the rescue.
Harley can be kicked around the island in a manner similar to the beach ball or gilded cabbage. However, the counter tracking how many times he has been kicked will always be one.