So, I'm curious, is this a Mr. Beer product or a Mister Beer product? Do you see the difference I'm getting at.
It sounds like it's a can of extract and I know Mr. Beer makes a nut brown ale can. Usually you combine that can, the can should be about the size of a can of baked beans, with some other fermentable materials, either their booster product, more liquid extract or dry extract, to make about two gallons of beer. It will produce a drinkable beer with little effort, but probably nothing spectacular.
There is also a product called Mister Beer I found online. However, this looks similar to something I saw at a homebrew shop in southern Washington while visiting my brother, yeastlvr on this site, a few months back. It's a two liter soda bottle filled with unfermented wort and it had a little yeast pill that you dropped in and let it ferment and carb in the bottle and then, when it was finished, that's when you take it home and enjoy it! It sounded awful, but in retrospect, I'm wishing I had picked up a couple of them to try out.
It sounds like this is a Mr. Beer can, because the little brown keg fermenter that got tossed sounds exactly like the Mr. Beer fermenter.