Vile Tentacles
Vile Tentacles can be found as loot from the Maddening Horrors inside Stygian Abyss Dungeon.
Since 1st Nov 2019 there is a new receipe in the Fellowship vendor for converting the Mace and Shield Reading Glasses in a new look called Cowl of the Mace and Shield.
10 Vile Tentacles are needed to craft the new item.