"Get The Grease!"

At work yesterday, for some reason the conversation between me and one of the other Submariners I work with turned towards some of the pranks we boat types used to pull on each other. Some of the more disturbing ones involve things done to people while they're asleep or otherwise incapacitated. Whether it's a Shellback getting silver nitrate "teardrops" applied to his face as he sleeps during the 'Wog Rebellion or the poor guy who got stuck behind some piece of machinery having unmentionable things done to him, the lesson we Submariners learn early is "don't leave yourself vulnerable".

Confession time: what's the worst thing you've done (or seen done) to a shipmate who was unable to effectively defend themselves?