A guy comes home from work on Halloween and finds his wife naked in bed, apparently asleep. He's thinking that maybe he has time to slip in with her for a quickie when his 5 year old son runs in saying "Daddy, there's a ghost in the closet!"
Trying to get the kid to leave, he tells him there are no such things as ghosts but the kid keeps saying
"Daddy, there's a ghost in the closet!"
Finally he goes over and opens the closet door to show the kid there's no ghost and he finds his best friend Fred clad only in a bedsheet. The guy looks at him and says
"FRED, What the hell's the matter with you scaring my kid like that??!!"