Krampus (species)

The Krampus were the stuff of folklore. They fed on negative emotions like fear and sadness, feelings they needed in order to exist.

They were Gaseous creatures, known to take the form of half-man/half-goat creature with horns and a long thin red tongue not dissimilar to the Daemons.

They had been known to create those feelings using a red psychic fog to separate people from their loved ones mentally. In the village of Hollograd the fog separated the parents and children on Christmas eve. The Doctor was able to disperse the fog with the roof light of his TARDIS. (DWAM: Red Christmas)