This is the iStab, a 3-D printed iPhone case with a folding knife attached. That way you can accidentally Van Gogh yourself while answering a call. Or you could, I don't know, just carry a far more practical folding knife separately from your phone. That's what I do. It's never actually come in handy, but I'm just waiting for the day somebody needs emergency surgery on the bus. "Somebody help, this man needs a doctor!" Don't worry -- I've got this! *stab stab stab* "What have you done, he was only choking!" *ringing bell* I'll just get off here.
Keep going for a couple more shots.
Thanks to BBQ, who agrees the best phone case isn't a physical case at all, but a force-field barrier summoned by the wizard who sells spells out of the back of his van at the Fairfax Flea Market on Sundays.