Episode 18 of "Buffy, the Vampire Slayer"
s02e06 Halloween
Title: Halloween
Original Air Date: 10/27/1997 on WB
Director: Bruce Seth Green
Writer: Carl Ellsworth
Guest Stars: Robin Sachs (Ethan Rayne)
Plot Outline:
On Halloween, Buffy, Willow and Xander are 'volunteered' by Principal Snyder to take groups of kids trick-or-treating. They get their costumes from a new store run by an Englishman, Ethan Rayne. Xander chooses a soldier outfit, Buffy buys an 18th century noblewomans dress to impress Angel... and Willow, despite Buffy's attempts to get her to dress in a sexy skirt and halter, dresses as a ghost. Unfortunately Ethan turns out to be a bad guy and casts a spell to transform everyone into their costumes. Xander is now a real soldier, Willow is a real ghost (without the sheet), and Buffy is at the mercy of Spike, who uses the convenient event to go after the now powerless Slayer. Willow goes for Giles' help who, it turns out, has a bad history with Ethan and beats the spell reversal out of him. Buffy is released from the spell just in time to save herself from Spike.