A type of play that is meant to create confusion in the defense by using uncommon formations or making certain offensive players eligible to catch the ball who are not usually eligible. Receivers may act as quarterbacks and quarterbacks may act as receivers, for example.
Sometimes referred to as "razzle dazzle"
Trick plays are more often seen at the college level because NFL defenses are very sophisticated and not often fooled by trick plays. Some teams, however, use trick plays as part of their standard offensive package. The Miami Dolphins, for example, have a "wild cat" option where a running back with receive the snap from center and pass the ball to receivers, including the quarterback who runs out on a pattern. A reverse is another type of trick play where multiple handoffs in the backfield create confusion for the defense.