Marcel Duchamp's "Fountain"

Origin
"Fountain" is a 1917 work produced by Marcel Duchamp (1887 - 1968) a French, naturalized American painter, sculptor, chess player and writer whose work is associated with Cubism, conceptual art and Dada. Duchamp is commonly regarded as one of the three artists who helped to define the revolutionary developments in the plastic arts. "Fountain" is a porcelain urinal, which was signed "R.Mutt" and submitted for the exhibition of the Society of Independent Artists, in 1917. The strangest thing about the piece was that several performance artists have attempted to "contribute" to the piece by urinating in it although no one has been able to claim the prize as the original was switched out with a replica.

Effects
Viewers have to use the restroom if looking at it for a minute of more.