Ghost Maggot
Source: World Event. If a live maggot eats the dead, what does an undead maggot eat? Undead type.
Ghost Maggot is a Hallow's End battle pet introduced in 2015 that spawns in your Garrison after applying 
Creepy Crawlers, a decoration purchased with 
Spooky Supplies from vendor Izzy Hollyfizzle.
Guide awaiting review
Purchase Creepy Crawlers Decoration
Buy the Creepy Crawlers decoration using Spooky Supplies from Izzy Hollyfizzle — Horde players find her at the center of the Garrison by the fire, while Alliance players find her next to the water fountain at the center.
Apply Creepy Crawlers to Garrison
Use the Creepy Crawlers decoration in your Garrison to trigger battle pet spawns, including Ghost Maggot, Ghastly Rat, and Spectral Spinner, scattered throughout the area.
Farm a Rare Ghost Maggot
Pick a single spawn location and kill any non-rare Ghost Maggot without battling it — a new pet will instantly respawn in the same spot, which can be any of the three pets, letting you cycle through spawns until a rare Ghost Maggot appears.
Capture With Terrible Turnip
Once a rare Ghost Maggot spawns, forfeit once to heal your battle pets, then re-engage and capture it — a Terrible Turnip works well if you are having trouble avoiding an accidental kill.
Tips
After finding a rare Ghost Maggot, forfeit the battle once to heal your battle pets before re-engaging to capture it.
