The final defense is one that is disguised as a person-to-person
defense, but is really a zone defense. In this form, it is usually
only effective for one or two passes. It is called the clam
and is shown below.
Everyone marks an offensive player so that the offense believes it's a person-to-person defense and stack up. The player marking the disc marks straight up (usually a no-no). What area a defender will cover depends on what position his/her check takes in the stack. As soon as the disc is in play the first two players in the stack get ready to poach on either side of the disc. As soon as any offensive player moves, these players take a position in the passing lanes. When the offensive players notice something is wrong, the next two people in the stack take positions behind the poachers. They stay about 10 yards behind the poachers no matter where the poachers go. The last two people in the stack will decide who should watch long and who should patrol the middle of the field. Since the force is straight up, a huck should be very difficult to get off.