"Trick or Treat - Smell my feet...." I think the smelling is the trick you have to do to get the treat!
Fond memories of my Dad asking the 8-12 year olds what kind of trick they were going to do to get the treats. There was one little girl who piped up quite proudly that she could do a cartwheel and then did one! Needless to say the big softee gave her an extra hand full while grinning from ear to ear.