Change visibly the shape of a shadow. Very easy to do and instant reset.
Effect:
You show a small plastic sculpture as your prediction and some cards with superhero names on them. A spectator selects a card/superhero.
You light up the sculpture with the light of your smartphone and the shadow on the wall reveals a question mark.
You visibly rotate the sculpture and the question mark morphs into a face. It is not the superhero the spectator selected. You pretend it's the correct guy that didn't put his costume on... You then shake the light slightly and the shadow changes into their superhero.
Comes with plastic gimmick + online video explanation