I believe I've discovered a small casualty of editing. Check here:
Robe of Bones
Aura moderate necromancy [evil]; CL 6th
Slot body; Price 2,400 gp; Weight 1 lb.
DESCRIPTIONThis sinister item functions much like a robe of useful items for the serious necromancer. It appears to be an unremarkable robe, but a character who dons it notes that it is adorned with small embroidered figures representing undead creatures. Only the wearer of the robe can see the embroidery, recognize them for the creatures they become, and detach them. One figure can be detached each round. Detaching a figure causes it to become an actual undead creature (see the list below). The skeleton or zombie is not under the control of the wearer of the robe, but may be subsequently commanded, rebuked, turned, or destroyed. A newly created robe of bones always has two embroidered figures of each of the following undead:
* Human skeleton
* Wolf skeleton
* Heavy horse skeleton
* Fast goblin zombie
* Tough human zombie
* Plague ogre zombieCONSTRUCTION
Requirements Craft Wondrous Item, animate dead; Cost 1,200 gp
Checking the Bestiary there are notes in the Zombie listing for how to create Fast zombies and how to create Plague zombies but nothing about how to create Tough zombies or what a Tough zombie statblock might be.
Any speculation as to what this is, or perhaps an official answer with the necessary spell and statblock that I expect were cut for lack of space?
