A flying crypid native to Java said to resemble a giant bat or flying primate.

In 1925,

Dr. Ernest Bartels is exploring a waterfall on the slopes of the Salek Mountains in Java when a giant unknown bat, the Ahool, flies directly over his head.

Two years later in 1927, around 11:30 pm, Dr. Ernest Bartels encountered the Ahool again, this time he was lying in bed, listening to the sounds of the jungle when he suddenly hears the distinct cry “ahOOOooool”.

Grabbing his torch, Dr. Bartels ran out of his hut in the direction the sound seemed to be heading. As he would recall many years later, he was transfixed on the sound, not because he did not know what produced it, but rather because he did, the Ahool.

At one time, Bartels had suggested that perhaps the creature was not a bat, but possibly a very large owl. This theory did not sit well with others who assured him in no uncertain terms that they were more than capable of distinguishing a bat from a bird.