If you've ever seen a jellyfish in the wild, at an aquarium, or in one of those 11-minute-long relaxation videos on YouTube, you've probably wondered: What are jellyfish trying to do? What is their goal? The answer is not entirely obvious, as these barely sentient blobs seem to senselessly ferry themselves from one place to another just because they can. Now, new research gives overthinkers yet another reason to envy jellyfish. Apparently, some of these animals without brains might sleep pretty peacefully.