If you get there last, leave a message

There’s a scene in Three Little Pigskins where Moe and Larry are arranging to meet at a predetermined location:
Moe: If you get there first, put a chalk mark.
Larry: Okay. What if you get there first?
Moe: Then I’ll rub it out.1
Anyway, The Reg reports that scientists have done this, only better, sending a message from one photon to another that that was already deceased.

Measuring P1 destroys it; even so, it gets its state from P4
Image: Phys. Rev. Lett. 110, 210403 (2013)
DOI: 10.1103/PhysRevLett.110.210403

1The Marx Brothers may have done this first, but I can’t locate the scene.