Exterminate!

Strange noises have been coming from an abandoned house on the edge of Ponyville. Word is that there is some kind of infestation in the house. But what kind of infestation?

A team of four ponies are called in to exterminate whatever is hiding in the old abandoned house on the edge of Ponyville.
There's only one catch. What infested it?
Find out in this fanfic