Bakumon

Bakumon (バクモン)
A Digimon which has the appearance of the Baku, said to be a dream-eating mythical beast. It is thought that it is a Digimon that was generated from a medical computer for detecting brain waves, and it seems that it uses the data from humans in REM sleep as nourishment. In recent studies, it has been proven that it has the power to purge particularly bad nightmares and malignant computer viruses. Also, since it has the ability to change the captured nightmares and viruses back to normal, it is considered a holy Digimon. There is surely some kind of connection between that sacred, unique ability, and the "Holy Ring" which it wears on its foreleg. Its Special Move is releasing its captured nightmares all at once, drowning the opponent in terror (Nightmare Syndrome). This is the same technique as that of the Perfect Digimon, Digitamamon, but its connection to Bakumon is a mystery.

Etymology
Baku: The Baku (獏) is a mythical animal, similar to a tapir, believed by the Japanese to eat dreams.