The 1937-D “3 Legged” Buffalo Nickel
is unique type of error which remains very popular with collectors. The coin takes its name from the fact that the buffalo on the reverse of the coin appears to only have three legs. Collector fascination with this unusual appearance has made this one of the most famous coins of the 20th century.
The error was created when a newly hired Denver Mint employee attempted to remove clash marks from one of the reverse dies. His die polishing successfully removed the marks, but also inadvertently removed one of the buffalo’s legs. The mistake was not realized until most of the coins had already reached circulation.
Both PCGS and NGC identify the Three Legged Buffalo Nickel by including “3 Legs” on the holder. Pieces are in demand in all grades, but especially so in mint-state.
Between the two major grading services, approximately 20 pieces have been graded MS66, with two coins graded MS67 by NGC. One of the examples graded PCGS MS66 sold for $80,500 at auction in August 2007. In more recent years, other examples carrying the same grade have sold for around $50,000.
taken from: http://buffalonickel.org/