DARPA launches projects that sound incredibly unrealistic from time to time. However, DARPA has also created actual working items that started out as incredibly unrealistic sounding plans. That means you can never discount DARPA when it puts out brief on a plan that sounds far-fetched at first glance.
DARPA's most recent plan is one such far-fetched sounding project that may be just crazy enough to work. The latest plan is called the Upward Falling Payloads project and is aimed at developing storage capsules for military assets that would allow devices, such as drones, to be stored at the bottom of the ocean for years at a time until needed. The idea is that capsules can be dropped at strategic locations holding drones or other items and the capsules could release their payload when needed.
The plan calls for unmanned, distributed systems to provide the military with operational support including situational awareness, disruption, deception, and rescue. One of the potential payloads for these capsules are small aerial drones that can launch to the surface in capsules, take off, and provide observation or act as decoys. DARPA is calling for input on finding ways of extending survival of capsules under extreme ocean pressure.
DARPA also wants to find methods of waking up these underwater nodes after years of inactivity. The plan also calls for input on ways to efficiently launch payloads to the surface. That last part doesn't seem too complex since submarines have been launching payloads to the surface of the ocean for a long time. DARPA is pointing out that this is not a weapons project and that the risk of losing any single node in the system is minimal.