Randolph the Blood-Nosed Caribou

The hat was released as a promotion for the steam 2013-2014 Winter sale. The item could be unlocked by crafting all ten sale-specific trading cards together. Once all ten cards were combined, you would receive a Steam Holiday Sale 2013 badge or a free-to-play game item. Team Fortress 2 was one of the free-to-play games participating, and the 'Randolph the Blood-Nosed Caribou' was the rarest item with the lowest odds of obtaining.

Only 2 exist, as confirmed by Valve.

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Randolph the Blood-Nosed Caribou

Team Fortress 2
Team Fortress 2 Limited Level 100 Hat
Granted by crafting the Steam Holiday Sale 2013 badge.
Tags: Unique, Cosmetic, Sniper, Tradable, Marketable