A revel is a wild celebration. Your context clue here is the detail that it went "whirlingly on". This gives the image that things are spinning and it is something that could end at midnight. An party hat doesn't end at midnight. A type of dance is something that can spin, but it usually doesn't continue on until midnight. A specific dance type usually only last for a few minutes. An appearance does not make sense.
Monsters are correlated with negativity, the evil inside of a person. The hero usually represents the will to fight back and keep that evil from hurting anyone. It's mostly opinion but that's just what I think I hope it gives you some ideas!
