Nudibranchs, or sea slugs, and are group of wildly colored animals that use their striking forms to warn predators against attack. Although the sea slugs move slow, they are protected by a brilliant defense mechanism. Some species create an alarming defense by stealing “weapons” from another creature called a hydroid. These plant-like animals may appear like seaweed, but they are actually a jellyfish relative covered in stingers packed with a paralyzing venom.

Instead of being repelled by the dangerous tentacles covering the hydroids’ bodies, nudibranchs devour them. Once swallowed, some of the immature stingers are passed directly into their digestion system and are stored in their spikes. If a sea slug feels threatened, these stingers are deployed for an overwhelming punch of stolen venom[…]

Source: These Sneaky Sea Slugs Paralyze Their Predators With Stolen “Weapons”