Que Horrifico is actually Mary-Ann Geerdon.
Mary-Ann wanted to scare people away so she can Crystal Cove her way. She lurned about the Legend Of Que Horrifico in Dr. Portilo's class.
She took some costumes from the stadium to make the Que Horrifico creature. She went to every kid and elementary school and convinced all the kids to be spookafied and she offered them utopia. But it didn't work so she offered them candy.
When Mary-Ann was in the Que Horrifico costume playing the pan flute that was the signal for the kids put their fakes hair and fang to make them look like Terrorbogattoes.
Mary would have to if it weren't for those Hommetto Boys Cabuela (it actually meant Meddelesome kids in Latin).