“Rubber bullet” is the common term, but it’s a bunch of crap. Most of the time it’s a huge metal ball wrapped in a thin sheet of rubber, which delivers about half the force of a live ammunition bullet.

Criminal was stealing police munitions, deviously stashed in a skull cavity where authorities have no way of seeing; had to be shot

Edit: in the future, routine security checks will have to include the inside of the skull, to be cracked every time you walk into a secure building like a courthouse, airport, or ration distribution center. Thank these fucking commies for that, since they just love hiding bullets in there so much.