Vamdemon

Myotismon is an Undead Digimon whose Japanese name and design are derived from the mythological Vampire and Demon, and whose English name is derived from the Greater mouse-eared bat. As the king of Undead Digimon, it was resurrected through the dark arts and obtained mighty powers. Originally a brutal computer virus which destroyed the computer data it absorbed, it possessed the ability to revive the destroyed data as malignant computer viruses. As the owner of an extremely cruel and cunning personality, it is exceedingly difficult to destroy this Digimon. However, it cannot demonstrate its powers outside of the night, and its power is cut in half during the daytime.