Maybe he's promoting you so he needs someone in your current position!!

Some people are just plain retarded. That means you're up for a promotion. If you were fired, they would've fired you then asked you to train your replacement OR just plain fire you.

That's cold.....

Perfect payback higher the worst employee put there

Maybe he is going to promote you and this is a test of charactor.

Just hope that it's because you're getting promoted.

You can do as the boss requested. However, was it specifically mentioned that your replacement actually has to be good at the job? The boss said find a replacement, you can really get creative... Unless you are to be promoted

Pick the best possible person for the job that you can find. Not because it might be some hidden test as to your suitability for promotion, not because the company deserves it. Because you are an awesome person who will do the right thing, regardless of whether the people you're doing it for have earned that effort, and doing the right thing makes you EVEN MORE AWESOME. Besides, you might need a reference from them someday.

Really? That happens? I would walk out of the job instead of doing that.

Hire the most incompetent and asinine twat you can find.