To play a trick on someone in your dream indicates that you are not being honest with yourself. You are trying to divert attention elsewhere, other than yourself. Alternatively, the dream may be a metaphor for "turning tricks."
To dream that you have been tricked suggests that your plans are about to backfire.
To dream that you are trick or treating represents the rewards you get when you set your mind to pursue your goals. The dream is also telling you that you need to learn to verbalize your desires in order for others to know what you want.
To dream that trick or treaters are knocking on your door denotes your desire to share your indulgences with others.