A jarhead is a man whose human head has been replaced with a plain glass jar. The jarhead operation was originally only used on US marines. President Teddy Roosevelt came up with the idea, just after his Rough Riders disbanded due to a plague of saddle sores. Roosevelt chose to surgically implant jars because of both the built-in storage and camouflage uses. Sometimes a Cuban falls in by accident, but these inept feeders are quickly digested and no harm is done to the jarhead.