It could be easy to miss a blob the size of a golf ball. But its blue hue—the rarest color in nature—stood out against the sand, grabbing researchers’ attention. It wasn’t a blob but an adorable blue ...

A blue-ringed octopus small enough to sit in a human palm carries a neurotoxin load that toxicologists describe as potentially lethal to multiple adults, yet doctors still have no antidote and must ...