The rarity of Ferocious Toxicant is Mythical, and been equipped it takes a “Bundle” slot. At this moment the item is available for trade.
Ferocious Toxicant is a skin for Venomancer. The skin was added to the game on October 16, 2015, it was created by Keanhotshine.
Ferocious Toxicant is currently one of the most popular skins, but it is rarely seen in the game due to its high price.