Thief's Downfall

Thief's Downfall (or The Thief's Downfall) is a waterfall that can be released over the track at Gringotts that has the effect of washing away all enchantment and all magical concealment.

When Harry Potter, Ron Weasley, Hermione Granger and Griphook access Gringotts and travel to the Lestranges vault by cart, the waterfall was released and it removed the effects of Polyjuice Potion from Hermione, a number of small charms and Transfigurations from Ron, and lifted the Imperius Curse from Bogrod.