Robojelly is a mechanical jelly fish.
The Navy had it developed for surveillance purposes and recently announced the program. The propulsion system imitates the movement of jelly fish.
Heat is created by the reaction of platinum and water. Platinum black powder reacts with hydrogen and oxygen to make heat and cause the segments to contract and expel waster miming the throbing of a real jelly fish.
The Robojelly is still in development. It will swim by using external hydrogen as a fuel. Steering the Robojelly is still a work in progress.