I had a pump come in for a rebuild a few weeks ago, it was rattling but sounded like it was in the motor, he decided to see how long it'd last instead of replacing it straight away. This is what he brought back yesterday.
I've NEVER seen anything like that, and I can't find anything wrong with it...... the crank bearing is ok (incredibly) and there was nothing inside the cylinder.
my guess it that the connecting rod snapped, then the floppy pieces proceeded to beat the snot out of everything.