Spectral Spinner
Drops from Maexxna. As if a mine full of non-ghost spiders wasn't scary enough. Undead type.
The Spectral Spinner is a Hallow's End battle pet introduced in 2015 that spawns in your Draenor Garrison after using the 
Creepy Crawlers decoration.
Guide awaiting review
Purchase Creepy Crawlers Decoration
Buy the Creepy Crawlers decoration from Izzy Hollyfizzle using 
Spooky Supplies — she stands at the center by the fire in the Horde garrison, or next to the water fountain at the center in the Alliance garrison.
Apply Decoration to Garrison
Use the Creepy Crawlers item in your garrison to cause Spectral Spinners, Ghastly Rats, and Ghost Maggots to spawn all around the area.
Hunt for a Rare Spectral Spinner
Engage a Spectral Spinner and check its quality — if it is not rare, forfeit the battle, then kill the pet and it will instantly respawn in the same spot as a new pet, which can be any of the three halloween pets. Repeat until a rare Spectral Spinner appears, then forfeit once to heal your battle pets before engaging to capture it.
Tips
Spectral Spinner has 5 known breeds, including S/S (Speed 325 at level 25) and P/S (Power 289, Speed 289 at level 25) — choose your preferred breed before capturing.
Rare Spectral Spinners can be extremely difficult to find; one player reported 9 hours of hunting before securing a single rare capture.
