living hairball

today i was followed to work by this little thing i can only describe as a black killer tribble with teeth, the thing appeared in the bathroom and it attacked me there, it had red eyes and a huge mouth full of deadly looking fangs, the thing tried to bite me but it was easily shaken off, you see it has no legs or arms, but it seems to roll for locomotion, it took me 30 minutes to beat this thing down and i need advice