Landsoul's Horned Greathelm

Source
This item drops from the Blood Prince Council in the 25-man version of Icecrown Citadel.

Trivia
Some have rumored that this helmet is a tribute to Landsoul of the guild , on Alterac Mountains, in recognition of his efforts on the DPS warrior spreadsheet found on Elitist Jerks. However, no blue posts have ever confirmed this to be the case- and in the absence of such authoratative validation many argue that these rumors were started and spread by this particular individual himself.