I didn't mean it was someone trying to be funny - I think maybe it's students from the college that don't like Mike, for some reason. They could've seen him getting in and out of his car, known his last name and googled his address. If you're going to be working in a public place with students, Mikey, get an unlisted number and address. If the kids were drunk or high, or whatever, they did benign stuff this time, but you never know what might happen if Katie's home alone one night.