The rarity of Tail of the Slithereen Knight is Uncommon. At this moment the item is available for trade.
Tail of the Slithereen Knight is a skin for Naga Siren. The skin was added to the game on July 22, 2013, it was created by Anuxi.
Tail of the Slithereen Knight is currently one of the most popular skins, but it is rarely seen in the game due to its high price.