You shift the coffin lid...

There is a small man-thing fluttering near the eyesockets of the corpse. It's green body is so small and glistening it almost looks like a shiny eye. As you try to grab him he hisses and bites your finger, leaving two needle like holes that hurt only slightly.

You try to grab him again and he glows like a roaring fire! You quickly snatch him and put him in your pockets. But he is still glowing yellow through the fabric of your pants...

He may come in useful.