The only known trebuchet casualty in history
arstechnica.com
arstechnica.com
There have been some serious injuries, too:
https://www.oregonlive.com/washingtoncounty/2006/10/child_tv...
Trebuchets were used for a variety of purposes in siege warfare, from (uniquely) breaching walls with large boulders to (less uniquely) setting things on fire to (probably) suppressing massed formations of archers with smaller shot. But smaller shot would not leave a characteristic trebuchet injury, it would leave a generic blunt-force trauma injury.
I learned that from Monty Python and the Holy Grail.
It's pretty clear he didn't pull that off...