Another way is to find any animal that is bigger then you.
IE: Fox, Mouflon(Sheep), Boar, Auroch(Cow), or Bear.
The first the first three have an option to kill you while you are KO'd.
If you pull an Auroch hair, they have a tendency to get pissed and stomp your head into the ground. Well, it's a combination effort of the entire herd doing as mentioned. But, still killing you.
Bears will kill you no matter what.
So, if you want a 100% chance of death, go wrestle a bear.