the guise the demon used to manipulate Sunnydale's mothers.
the demon's true form.
The Hans-Gretta Demon was a minor antagonist in Buffy The Vampire Slayer, taking the form of two ghostly children known as "Hans" and "Gretta" this malevolent spirit corrupted the mothers of Sunnydale into a modern day witch-hunt, causing them to increasingly oppress anyone they believed was practicing "magic" (regardless of its origin): to the point that they would attempt to burn their own children at the stake.
Buffy learned that the Hans-Gretta Demon had been doing similar stunts for centuries and was the inspiration of the fairy tale of "Hansel and Gretel" - ironically in Buffy legend it is suggested the witch that was killed in the story was in reality a victim rather than an antagonist and the Hans-Gretta Demon seemed to exist to manipulate people into killing "witches".
However when Buffy and her friends finally managed to break the Hans-Gretta Demon's hold on the mothers' of Sunnydale its guise fell to reveal its true self - a gigantic ugly monster that demanded the mothers defend it, however Buffy noted that its pleas weren't so convincing in its new form.
Realizing it was foiled but wishing to take out the Slayer in the process for revenge, the Hans-Gretta Demon charged at Buffy but was impaled on one of the wooden stakes - ending its rule once and for all.