According to current memory, that would be an item known as "The Cannon", I believe. I'v probably seen worse but just forgotten about 'em.So... what was?
Though technically it'd probably the "The Penetrator" from Saint's Row 3, which is sort of a combination of a dildo and a baseball bat. You can beat people do death with it.
And versions of it do exist in real life, so it does count.
Why do I know so much about this subject? I'm a horrible person...