The magician makes a few magical passes over a dead body, after which the corpse reanimates and speaks. When the magician realizes that it is not good to play with the forces of life or death, the spell is canceled and the corpse falls lifeless once again.
This is a fun effect that can be performed at open-casket funerals (in much the same fashion that "The Inadvertently Decapitated Bride" illusion is performed at weddings).
While bending over to "pay respects" to the departed, loops of fishing line are used to loosely connect the corpse's and magician's wrists. The line is long enough to let the magician get about two feet away before the corpse's arms are pulled into motion.
The magician can make magical passes over the corpse while the line is slack. Then, by stepping back and pulling the lines taught, can cause the corpse to raise its arms and sit up in the coffin. From this position, the arms can be moved in marionette fashion, pointing accusingly, gesturing in anger to the sky, doing card tricks, etc.
A little ventriloquism is also very handy here. In an imitation of the departed one's voice, the magician says something like, "So, who didn't I kiss goodbye? Come on, form a line," or perhaps "Does being dead make me look fat?" It all depends on the corpse's one-time personality. If the magician can't think of anything appropriate to say, a medley of show tunes might be substituted ("Tomorrow," "I Feel Pretty," "Oh What a Beautiful Mournin'," etc.).
When the time is right, the magician simply breaks the fishing line and the corpse collapses back into the coffin. What a finish!
Note: At a closed-casket funeral, a little surreptitious knocking on the side of the coffin and some ventriloquism ("Let me out of here!" or, more cleverly, "I'll get you for poisoning me, Jim, you bastard!") generally suffices to lighten the mood without any disrespectful handling of the corpse. If there was a cremation, a magician will stick with a simple urn levitation.