Slim Bankshot was a ghost in the game Luigi's Mansion. He was pool shark but now he has no one to play pool with because he's dead.
How To Beat Him
To beat Slim Bankshot, you need to wait until he circles around the pool table and then when he fires, suck up pool balls and shoot it at him. You can then try to suck him up. If you didn't suck him up the first time just do the method again.