Extens (Gimmicks and Online Instructions) by Victor Zatko

A New Classic In Card Magic. Imagine dipping a piece of ordinary wire into hot liquid, and it instantly changes into the shape of a previously selected card!

A spectator signs a piece of paper. The paper is left face up on the table. From a deck of cards the spectator selects a card. The whole deck is put on the paper. You tell that there was an invisible prediction written on that paper. The spectator shows his card and the magician lifts the deck. On the very same signed paper there is the number and the suit of the selected card! 

Having an invisible deck of cards become visible and proving it by also having the freely selected invisible card instantly become visible as well having a spectator call a friend who eerily names the one card you have turned over in the deck prior to the call Or, many, many other uses.