A mysterious pink phallus-shaped glass is one of the more unusual lots offered in Christie's Out of the Ordinary sale in London on September 14.
It's believed to date to the late 19th or early 20th century and was clearly made by a skilled craftsman, although its origins are unknown.
While glassmakers were known to produce such objects, this bears no maker's mark.
As to its use, Christie's suggests it may have been created for one of the many underground drinking clubs attended by the upper classes in England at the time.
For example, the Hellfire Club, for example - really a loose grouping of several clubs linked by the moral outrage they roused - delighted in satanic imagery and sexual abandon.
Sir Francis Dashwood's Order of the Friars of St Francis of Wycombe was perhaps the best known of these clubs.
The group would meet twice a month in a network of caves carved out under Dashwood's home of Medmenham Abbey in Buckinghamshire (which can still be visited today).
Dressed as monks, they would get riotously drunk and perform black magic rituals before partaking in orgies with prostitutes.
Another group known as the Wig Club - which operated mainly as a gambling den - is known to have used glasses like the present one in their drinking games.
The lack of information concerning the cup makes it impossible to place, but the mystery surrounding it is likely to intrigue collectors.
It's valued at £3,000-5,000 ($3,980-6,633).
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