Doc Ock Lives!
Okay, not quite, but a group of US Universities funded by DARPA (the U.S. Defense Advanced Research Projects Agency) has created a robotic tentacle that might one day be used to create, among other things, a backpack with extra arms! It’s Doc Ock come to life! Admittedly, the arms probably won’t have true artificial intelligence. And admittedly, they’ll probably use something a little more secure than just an external chip clipped to the back on the subject’s neck to prevent that. 
More practically speaking, it’s hoped that these new robotic arms, which actually seem a lot more like an elephant’s trunk than an octopus’ limb, will be useful for sensitive work such as bomb disposal, remotely searching for survivers of disasters, or other sensitive work that can’t be done safely by humans. They really are a pretty remarkably feat of engineering - check out their website, which includes some great videos, especially the one where the arm steals and defends its prize - a can of Coke!