A squid is a soft-bodied ocean animal with eight arms, two longer tentacles, and a torpedo-shaped body. Squids are mollusks, relatives of snails and clams, but instead of shells they developed speed and intelligence. They propel themselves backward by shooting water through a tube-like funnel, like living jet engines.

Squids have remarkable abilities that seem almost like science fiction. They can change color instantly to blend with their surroundings or flash patterns across their skin. Their large, complex eyes rival human eyes in sophistication. When threatened, many squids release a cloud of dark ink to confuse predators while they escape.

Squids range from tiny creatures an inch long to the colossal squid, which can grow longer than a school bus and battle sperm whales in the deep ocean. People eat squid in many cuisines: you might see it on a menu as calamari, the Italian word for squid. Fishermen catch millions of tons of squid each year, making them one of the world's most important seafood sources.

Scientists study squids to understand ocean ecosystems and to develop new technologies inspired by their jet propulsion and color-changing skin.