Effect:
The spectator picks a card and signs it.
Magician splits deck in two piles
The spectator picks a card and signs it.
Magician splits the deck in two piles
Then he puts the card in one pile and it magically appears in the other.

This is called teleportation…

Completely impromptu
works with a borrowed deck

no sticky stuff
no magnets
no threads

Works even with a card from a different deck.