If you were to hit it you would knock the boat's brains out.
Things float around loose, ready to knock your brains out when the drive goes on.
They try to fly through it and knock their brains out.
He wasn't trying to knock out my brains anymore.
At last he rode full speed against a tree, and nearly knocked his brains out.
Give me back Sydney, or knock out my brains.
I'm liking life too much to knock my brains out.
"The time they start pitching around the guy in front of him, he's going to knock their brains out."