When it comes to angling for big predatory fish, live bait is almost always the best way to go. Those bait fish must be caught and kept in a special "live well" aboard the boat, however, plus they'll inevitably tire out after spending much time at the end of the line. That's why Boston-based Magurobotics created the Zombait – it's a vaguely creepy device that makes dead bait fish move as if they're still alive.
To use the Zombait, users start by shoving the waterproof device down the mouth of the selected bait fish – different models are being designed to work with different sizes of fish. A monofilament line is then run from the still-accessible "mouth" end of the Zombait to the user-supplied hook or leader. That monofilament acts as a tether, and doesn't replace the main high-test line that runs from the hook to the rod and reel.
Upon contact with the water, a sensor in the Zombait causes it to start moving. As the back of the device moves back and forth, it moves the fish's tail with it, making it look as if the fish is swimming.
One charge of the removable lithium-ion battery should be good for two to three hours of use, with an included charger allowing users to charge up an extra battery while the first one is in use. The Zombait can withstand being submerged up to 200 feet (61 m).
If you're interested, the device is currently the subject of a Kickstarter campaign. A pledge of US$54 will get you one, when and if they reach production.
The Zombait can be seen in action, in the following video.