Here is my second version of Ambitious Card’s phase.
The spectator chooses and signs a card.
The selected card is placed in the middle of deck and the deck is placed inside of the box.
The magician shakes the box and the chosen card jumps on top of the deck!
The trick is IMPROMPTU.
No preparation is needed at all.
The box and the deck can be given to the spectator before and after the trick.