There's a window around eight to twelve where most children's entertainment stops working. Mascots are for little kids. A magic show gets watched with folded arms. The Gothic Girl exists for exactly that room, and she works because she is on their side of the joke — she thinks the party is ridiculous too.

The whole performance is deadpan. She doesn't do enthusiasm, she's reluctantly impressed at most, and the children spend the visit trying to make her react. Then the dance number happens — stiff, straight-faced, and performed with total commitment — and the entire room joins in. That's the bit parents film.

For younger siblings in the room she's harmless: there's nothing frightening about her, she just isn't aimed at them. If the party skews under six, the vampire or a mascot character will land better.