Ghost Corner by Gol D Iron/Inspired by Lubor Feidler 
A Haunting Mystery! 

You cleanly rip off the corner of a regular un-gimmicked playing card. You now grab the card where the corner once was and are able to control it and move it in all directions. 

- Can be done with many ordinary, borrowed objects. Playing cards, business cards, leaves, paper. 
- No threads or magnets or see-through plastic. To all appearances, you are literally grabbing air. 
- Self-contained gimmick. 
- Easy reset.