GUARDAMAR DEL SEGURA, Spain - Recent sightings of a tiny blue sea slug with a powerful sting have closed beaches in southeastern Spain. Blue Dragon sea slugs are around an inch long and have unique ...

At first glance, the blue dragon sea slug looks like something out of a dream: a tiny, winged creature painted in shimmering silver and electric blue, drifting gracefully across the ocean’s surface.

Blue sea slugs were believed to prey on the Portuguese man-of-war, which contains highly poisonous nematocysts, and uses the nematocysts for defense by incorporating them into the tips of its lateral ...