This is a shocking trick, and it's usually presented as a different kind of trick that's gone wrong. A magician might be balancing on an impossibly narrow point when they suddenly slip, and the point impales them, poking out through their chest or stomach.
Everything the magician needs to pull this trick off is under their clothes. First, there's a back brace which helps them to balance on the point, and then there's a corset that holds the 'point' that appears to have passed straight through their body.