Bulging Butthole
Somebody who is so generally offensive to both your senses and intelligence they remind you of a bulging butthole. I.E. Even being in the same general area as this person is equivalent to being forced to watch somebody bulge and pucker their sphincter in your face; it is utterly nauseating and intolerable.
God, I couldn't stand sitting next to that Captain Obvious over there now I get stuck next to the bulging butthole that just can't stop spouting nonsense at everybody. To hell with this, I'm outta here before the last of my brain cells die or I'm forced to choke this guy.