Some early Sonic Youth ("Protect Me You," "Ghost Bitch," "Halloween," etc.) could fit into a Halloween theme, but by your description the kids who'll be there would probably hate it. Also, they wouldn't fit at all into a dance environment, except for maybe some of the more up-tempo songs like World Looks Red, Brother James or Death Valley '69.
However, the Ramones' "I Don't Wanna Go Down to the Basement" and "You Should Never Have Opened That Door" should be great for it. Especially the latter.
Finally, the Decemberists' "Shankill Butchers" could work, although the kids might find it too slow.