If you enjoyed Bioshock Infinite, I have some good news for you. The Sky-Hook is real! As real as it is likely to get anyway. What you see here is an “Air Grabber” prop (the Rapture version of the Sky-Hook from Bioshock Infinite’s DLC).
This is a prop for an upcoming BioShock fan film from PCND FX. The details look pretty impressive and it even moves. Don’t try to jump and grab onto any rails though. The metal parts at the end do spin pretty fast, so the weapon part of it is definitely working.
Check out the video to see it in action. Don’t go sticking your fingers in there as it spins.