When Aang entered Forgetful Valley during Team Avatar's search for Ursa, his face twisted into a strange expression in a similar manner to what had happened when they first encountered the wolf spirit. Sokka pointed out that the face Aang was making was similar to the markings on a nearby flutter bat, and Aang attempted to follow it. The flutter bat, however, flew off, and Aang was forced to create an air scooter to keep up. The bat eventually reached one of the four pools in the forest, and Aang ceased his pursuit, believing that the flutter bat had been leading him to the pool. The flutter bat subsequently flew off.
After Aang crossed over into the Spirit World, he found the same flutter bat hanging from a tree, waiting for him. The flutter bat informed Aang that it could show him what he sought and flew Aang on its back across the forest to the location of the wolf spirit.
The flutter bat is a mixture of a bat and a butterfly, as its name suggests. It has the body of a bat and the head of butterfly, with a light yellow proboscis. It has two large eyes, and two large markings in the shape of eyes on its wings. It does not have any antennae, but instead has two indigo ears.
The flutter bat is a hybrid of bat and butterfly. Bats are the only flying mammal in the real world and can only be seen at nighttime. They live in caves, and always lie dangling and reversed, much as the flutter bat did when Aang was pursuing it. Butterflies are day-flying insects that stay near flowers and herbs. They are important as pollinators for some species of plants, although in general they do not carry as much pollen load as bees.