Disco Demon also known as Diabeł z Dyskoteki (pl. Rave party devil) was a Polish hoax demonic cryptid that was the soruce of many urban legends in 1980's and 1990's.
The creature was described a shapeshifter to some degree. It could turn itself into a human form and it's demon form, and was possibly fully sentient. It could however be distinguished from other humans by the fact that it smelled like sulfur and posessed hooves even in it's human disguise. The creature would then ask random person for an hour, and after the person would respond the demon would kill him or her, or some other person on the rave party and then mysteriously disappear.
From a political point of view, much like Poland's other demonic cryptid Black Volga, the Disco Demon propably was made as a hoax to scare people into not going to rave parties. The same thing applies to the Sataniści.