The rarity of Doomsday Ripper is Mythical, and been equipped it takes a “Bundle” slot. At this moment the item is available for trade.
Doomsday Ripper is a skin for Pudge. The skin was added to the game on April 28, 2016, it was created by Meshroom.
Doomsday Ripper has been recently added to the game, which makes it rather popular with the game community.