I decided to come downstairs and help him grab his luggage. He knew something was up, as I'd gave him a bit of warning, but nothing specific. When he walked in to his room, his jaw hit the floor. I could not contain my laughter.
Then I mentioned that he may want to open his drawers. I think, at that point, my laughter could be heard within a 3 mile radius. All in all, he took it in stride, and had a laugh as well. It was, by his admission, a damn good prank.
Although I'm obviously an ass, I'm not a total prick, and have been since helping him to clean up the damage. I will have a few more pics tomorrow. As for now, I'm very, very over anything that even resembles plastic wrap.