While the oven was preheating, there seemed to be a burning smell, like toast. I ignored this and went on to make my food, but the smell lingered.
Hours later, after a nap (where I awoke to a toast-like smell), I decided to investigate. There appeared to be a dark mass in back of the oven. My heart sank, as I wondered if I had the guts to remove what could be a dead mouse. I got the flashlight and aimed it at the offending object. It was small and roundish, dark brown or black... a croissant!
Whew!! I had heated some mini-croissants (700 calories for the whole box) the other day, and one must have fallen out of the pan. So the toasty smell was actually toast. Charred and blackened croissant-type toast.
Far preferable to dead animal toast.