Parasite Humor

A guy goes into the doctor's office to find out how to get rid of his tapeworm. The doctor tells him "Come back tomorrow with an apple and a cookie". So he does and the doctor shoves the apple into the patient's anus, waits five minutes and then follows it with the cookie. Then he tells him "Come back tomorrow with an apple and a cookie". So he does and again the doctor  gives him the apple enema and then the cookie enema. This goes on for a week and finally the doctor say "Ok, tomorrow bring in an apple and a hammer". He does and this time the doctor shoves in the apple and waits and when the tapeworm sticks his head out and says "Where's my cookie?", he whacks it with the hammer.