Using this item doubles all your stats for a single floor. (tested briefly and this appears correct, needs proving)
At 100000pix this is the most valuable drop that can be gained prior to Endgame where you get access to the Lapis Ruins and onwards. It will be difficult to sell due to it being a very unwanted category and likely too expensive for customers. Due to its extreme rarity it is best saved as it in total 4 are required to create the best weapons in the game.
If you find this item on your first successful attempt of defeating Griff and The Archdevil's Arm, you will not be able to pick it up unless you are quick about it.