The Bonereaper's Hook
Reaching the lab
Summoning ghouls with after reaching Artifact Knowledge 6 has a chance to summon an additional ghoul who will drop Professor Putricide's Lost Journal upon expiration. When the minion spawns, he will speak, asking "Why have I been brought back to fight for you?"
Reading the journal points you toward Putricide's Secret Lab via a trap door in Putricide's Laboratory of Alchemical Horrors and Fun in Icecrown Citadel. There you will find Stitchwork; kill him to retrieve the Hook.
You do not need to read the book in order to access the trap door, only summon the special minion. You can't read someone else's book for credit.
- Patch 7.0.3 (2016-07-19): Added.