Dude!

Reported in several places.

The prisoner, 29-year-old Gonzalo Montoya Jiménez, was found unresponsive in his cell during a morning roll call, and had been transferred to a hospital mortuary in a body bag when pathologists heard something strange.
Snoring. Coming from inside the bag.

We've all hard the horror stories of people being buried alive.  Mostly from the late 19th, early 20th centuries.  The practice of embalming has pretty much put an end to those stories.  Once you are pumped full of embalming fluid, the chances of waking up are pretty slim.