This is a squirrel that had made it's way into the chimney vent which was also the flue for the water heater and furnace. The flue cap had somehow fallen off which allowed for the squirrel to make it's way down. Unfortunately the squirrel had become trapped at the bottom of the flue where it connects to the water heater. This caused a venting problem for the heater and fortunately if shut off.
The homeowner tried to relight the pilot several times and it just kept going out. Eventually if wore out the ignitor and we decided to replace the water heater. As soon as I pulled off the flue for the old water heater this dead squirrel popped out.