One, because it's its spawn room.
Two, because you can't stop it.
Three, because
Uuaaaaarrgh.It's the monster in the closet, and no one has a chance at stopping it.
Not even Donald Annoying Orangeh can stop it because
'GhUgAraragf'
Link'd
You should demolish your closet and hind behind your fauteuil's. If you don't own any I suggest you purchase cruets, and be prepared to throw them at it.