Other mistake: When Striker says to Randy "You better leave sweetie, you might get hurt up here," watch Elaine who was trying not to laugh. (01:14:45)
Other mistake: In the credits, Kareem Abdul-Jabbar's name is misspelled Kareem Abdul-Jabaar. (01:23:40)
Other mistake: In the closing credits, Ann M. Nelson, who hung herself early in the film out of sheer boredom at Striker's longwinded story, is listed as the "Handing Lady" rather than the "Hanging Lady."
Other mistake: When Johnny reads in the folded newspaper, 'There's a sale at Penny's!', the viewer can read the headlines right way up - which means, from his side, he is holding the paper upside down.
Answer: This is a reference to The Godfather, where a character being intimidated by the Mafia wakes up with his prize racehorse's severed head next to him on the bed. For comedy purposes this is twisted by the movie as an implied sexual relationship, when the horse is revealed to be alive.