This very ghoulish lesson came about because I wondered if a person can die with a last facial expression that will stay. It didn’t seem to make sense, given that your facial expressions are caused by muscles, and dying makes your muscles relax.
Well, it doesn’t work for facial muscles, but bigger muscles like legs and arms and hands can freeze and stay that way, even after other muscles relax, even after rigor mortis resolves. It takes a lot for it to happen, and it is not pleasant.
If you’re up for it, here’s a two minute video on the topic.