Extra built up mold on brie cheese
....Honestly I'm guessing it is the penicillium candidum (the normal white brie mold), but you can't know from looking at the picture. Common sensically speaking, if the brie was properly wrapped up, then the other molds in your fridge are unlikely to have gotten a foothold on your brie, BUT it is possible for the other completely unknown molds in your fridge to have taken up residence without having formed visible colonies. So from that perspective, better safe than sorry.

Personally, as someone with a healthy immune system, if it were a fairly pricey brie, I'd cut off and toss the exposed edges of the brie, wrap it in puff pastry or pie crust, and bake it. But if it were fairly cheap, I'd probably toss it, and I hate wasting food and money.