When I was a hiring manager, someone did this to one of the guys that worked for me, except they called my boss, instead of me. He left a message that stated my employee smoked pot and that we needed to drug test him and have him fired. Well, the joke was on him, because I smoke pot and so did my boss at the time, and we knew my employee did, too. It was some asswipe that wanted to date my employee's ex-wife. My employee and his ex-wife weren't on great terms at the time and evidently she had been bitching about him to this dude, so he decided that trying to get him fired would win her over. It did not.
Since then, the dude that got NARCed on has been promoted a few times.