The Well of Forgetfulness is a location on Eternia that features in He-Man and the Masters of the Universe.
Located within the castle at Abra, the Well of Forgetfulness had a fountain with magical water that could cause anyone that touched or consumed it to forget their past and their identity.
The evil Count Marzo first used the water from the well to erase his memory of his dephew David of Abra, and later used his magic to create a vapor gun out of them as well.