What is this?

Last week, I padded into the kitchen around 11:30 to lock the back door, and so forth, before hitting the sack. A piercing light drew my attention; it came from the building next door, where new tenants had just occupied the third floor. Going to draw the curtain, I was confronted by a bushy-haired young man, standing staring in the bathing glare coming from his window on the other side of the alley. I pulled the curtain with a sigh of "what a weirdo."

The next day, this:

Yes, that IS tinfoil! Good eye!

Does my new neighbor read the government's emergency-preparedness website a little too closely (first duct tape, now tinfoil)? Is he growing dope? Is he just a cheap-ass bastard?