They were jellyfish, of course. There are around 2,000 species of jellyfish inhabiting all the waters of the world. They come in many shapes, sizes, colors and toxicity. Did I say toxicity? You bet I did. Jellyfish have no brain, no spine and no bones, but they do have a nasty sting. When anything brushes against the jellyfish's tentacles, the tentacles react, firing harpoons of poison into the victim. Since the jellyfish has no brain to direct assaults, the tentacles react independently, to touch stimuli. They are part of a "nerve net." This means even if the tentacles are no longer attached to the major body mass, or bell, of the jellyfish, they can still sting. Also, seeing a jellyfish washed up on the shore is no security against being stung. If the tentacles are wet they still may be able to inject you with poison. Although only a few jellyfish species can kill humans, most will sting, and the pain can last for hours. Best practice is to avoid touching jellyfish with your bare skin.
The jellies we gathered on the beach in Rhode Island were not harmful to humans. Still, even as children, we had been taught not to handle anything until we knew what it was. Sound advice. In July of 2006, Rhode Island beaches got a "jolt" when Portuguese Man-of-Wars invaded the coast. Although not technically a jellyfish (they are siphonophores, a colony of organisms that live and hunt together), the Man-of-War can be lethal to humans, and attacks with a powerfully painful sting even after it's washed ashore. So, when it comes to oddities on the beach, remember, no touchy.