Sea urchins are small, round animals that live on the ocean floor. They look like spiky balls because their bodies are covered in sharp spines, which help protect them from predators. Sea urchins use their spines and tiny tube feet to move around and find food. They have a special mouth called "Aristotle's lantern" that helps them scrape algae and seaweed off rocks to eat. You can find sea urchins in oceans all around the world, often hiding in rocky areas or among seaweed.

Sea urchins come in many different colors, like purple, red, and green, making them fun to spot while exploring tide pools. They play an important role in the ocean by keeping algae from growing too much, which helps maintain a healthy balance in the ecosystem. Some sea urchins can live for over 30 years and can even regrow lost spines. These fascinating creatures might seem a bit scary with their spikes, but they are important and amazing parts of ocean life!