Worst failed part found during HG replacement

[gears-n-grease]

Replacing the headgasket on my M30. Here is the old thermostat compared to the new one. I would love to know if the previous owner did this or where the rest of it may have gone.

[bitkill]

The previous owner cut it. It is a "common" thing to do when the car is overheating. You cut the thermostat because is an cheap part to replace when you suspect it is not working like it should.