I've been fascinated by these things long before I started playing D&D. A jellyfish with 50 meter long tentacles? Incredible that something like this really exists!
One of the races introduced in the Expanded Psionics Handbook, the Maenad are almost human in appearance but for their skin that seems dusted with fine, sparkling motes. They are wildly emotional beings making them excellent Wilders. In real-world mythology they were the female followers of the god Dionysus, their name literally meaning "Raving Ones".