And among the octopus and schools of fish, there they are: tiny, powerfully cute, neon-colored sea slugs. Nudibranchs (pronounced various ways, including NEW-duh-branks) are a family of sea slugs.

Stinging cells, produced by cnidarians such as jellyfish and anemones, are one of ocean creatures' most effective defences. This method of protection can keep almost all predators at bay - but not the ...