Maggots are critters that can be found in the Ghostlands, Naxxramas, Ashenvale, Hinterlands and Underbog.
In the real world, maggots can be a threat to livestock, especially sheep. Flies reproduce rapidly in the summer months and their maggot larvae can be produced in large numbers, creating an infestation.
Achievements[]
Killing one of these is required for 
[Pest Control].