A rare coup whereby a seemingly certain trump loser vanishes.

For example:

Hearts are trumps, and South, declarer, leads the ♠️9 from dummy. East ruffs and South will overruff. If East ruffs with the ❤️J, South ruffs with the ❤️A, and finesses the ❤️10. If East trumps with a lower card, South ruffs with the ❤️9 and takes the top two trumps for the final two tricks.