Another bit of irony:
risus sardonicus ['riːsəs sɑː'dɒnıkəs]
noun
(Pathol) fixed contraction of the facial muscles resulting in a peculiar distorted grin, caused esp. by tetanus
Also called: trismus cynicus
['trızməs 'sınıkəs]
[ETYMOLOGY: 17th Century: New Latin, literally: sardonic laugh]

I think it is also seen in death from tetanus.