The Merde d'Artiste (Shit of the Artist) were made in 1961 by Piero Manzoni (1933-1963), an Italian artist. The 100 handmade metal cans with fecal matter in them had printed serial numbers on them, and was in reality a protest against the pseudo-intellectual art-critics and collectors. In spite of the apparent inunitability of the piece with these lines of thought, the collectors bought all of the cans and they have amassed some quite high bids at auctions.
Recently, there was some controversy because a number of the cans had started leaking. A collector attempted to get his money back from the auction house, but did not succeed. Supposedly, this was part of the piece's concept.