Ghost Houses. They carry a fishing rod and ride a Lakitu's Cloud , much like the living variety. However, instead of a 1-Up Mushroom, Fishin' Boos carry a blue flame and follow Mario in a way that makes it hard for them to Jump. Their clouds also do not have eyes. A Fishin' Boo has the same immunities as a normal Boo and therefore cannot be jumped on.
They can also be eaten by the Hungry Boo.