Costume Bag (Deluxe)

If you use it, it will transform you into one of these 5 creatures:
Serpent Spawn
Demon
Juggernaut
Behemoth
Ashmunrah
It can last for approximately 5 hours. Note that you'll lose your costume if you go swimming, become invisible, get your appearance changed by a creature such as a Dark Apprentice, use a Chameleon Rune, die, use the spell Creature Illusion, use a Spellwand on yourself, or transform into a corpse for a few seconds (e.g. when passing out on mead). Also note that you won't be able to use a mount while you are transformed. Using 100 of these will reward you the Masquerader achievement