The gilacorn is a small, lizard-like creature that scavenges the Si Wong Desert, looking for food. Many years in the past, giant gilacorns were alive and posed a threat to a tribe living in the area at that time, the beetle-headed merchants. However, only the diminutive version of this creature was alive in 100 AG.
According to old legends, the subterranean ancestors of the beetle-headed merchants, the first humans living in the Si Wong Desert were constantly attacked by giant gilacorns until they mimicked the appearance of sour beetles, the only creatures on the desert floor not palatable to gilacorns. However, these giant gilacorns were extinct by 100 AG.
In the Si Wong Desert, one gilacorn stole an egg that Appa attempted to eat. After finding an egg in a nest, Appa was ambushed by the creature, who snatched the egg and quickly retreated, holding the egg over its head.
Long before Aang's time, gilacorns were equipped with a whimsical but deadly unicorn horn. In more modern times, it walks on its back legs like a basilisk lizard or a mongoose lizard as it walks on the surface of water.
Known to be the nanny-goats of the desert, gilacorns will eat anything except sour beetles.
- Part of the namesake of the gilacorn is the gila monster. Unlike its real-world counterpart, the gilacorn is somewhat smaller and faster.