Who'd have thought, a dancing demon. Wanting his relationship with ex-demon Anya to have a happy ending, Xander summons Sweet who arrives in demon and causes the whole to succumb to a whacky Broadway nightmare. There's singing and dancing galore, only the dancing goes to far and some residents end up combusting.
He sends his henchmen off to find the person who summoned him who he must now make his Queen. But since Xander cast the spell, Dawn has found the shiny trinket he used at stolen it, so she is one that ends up kidnapped. Of course a life-0weary Buffy has to come to the rescue of Dawn once again, and when Xander admits it he was one the one did the summoning, Sweet forgoes the whole 'Queen' issue and returns from whence he came.