During our favorite Halloween ep what if Buffy, instead of trying to impress Angel, had decided to let her hair down and have some fun? What if she decided to go as Harley Quinn instead of some brain dead noblewoman? What if Spike stole something from Ethan's shop to wear unknowing it was part of a Joker costume? 

So when the spell kicks in Buffy turns into the beyond crazy Harley Quinn and Spike turns into the Joker....her "Puddin"

What kind of mayhem could those two under go before Giles reverses the spell?!