One day, a man confined in hospital on the 13th floor with a severe case of diarrhoea, had a sudden rush to his bowels, so he went quickly to the toilet, only to find that it was a false alarm. 10 minutes later, he gets another rush in his bowels so he races again to the toilet, only to find that is another false alarm. The same thing keeps happening for several hours, all false alarms. Eventually, when he gets another rush, he decides to stay in bed, but it is no false alarm, he engrossed the bedsheets with faeces(and himself). Then in his frustrated state, bunches up the soiled bedsheets and hurls them out the window with irritation.
During the same time, a drunken drifter is pacing up and down the sidewalk of the hospital, is knocked over and blacked out by the disgusted sheets, and gets up to find that he is covered in poo, so he swings and kicks and curses at the sheets, and they fall on the ground, with the filth of the shit seeping out from the bedspreads.
Meanwhile, a Security Guard that has seen the whole thing, comes over to the drifter, who is dazed and confused about what has just happened. He asks the drifter, "What on earth is going on here??"
The drifter looks at the sheets, scratching his head and pondering over the possibilities, replies after some seconds, "Um...., I think I just beat the crap out of a Ghost!!!"