The ahool is a flying cryptid, supposedly a giant bat,^{[citation needed]} or by other accounts, a living pterosaur or flying primate.^{[citation needed]} Such a creature is unknown to science and there is no objective evidence that it exists as claimed.

Like many cryptids, it is not well documented, and little reliable information - and in this case, no material evidence - exists. Named for its distinctive call A-hool (other sources render it ahOOOooool), it is said to live in the deepest rainforests of Java. It is described as having a monkey/ape-like head with large dark eyes, large claws on its forearms (approximately the size of an infant), and a body covered in gray fur. Possibly the most intriguing and astounding feature is that it is said to have a wingspan of 3 m (10 ft). This is almost twice as long as the largest (known) bat in the world, the common flying fox.

According to Loren Coleman and Jerome Clark, it was first described by Dr. Ernest Bartels. Bartels published regular accounts of his work down there --> while exploring the Salak Mountains on the island of Java.