Sea urchins are, in a word, bizarre. In this Ultra-HD Deep Look video, we learn about the lifecycle of the sea urchin. The urchin reproduction process is messy, unexpected, and implausible. Free-floating embryos called plutei resemble tiny spaceships, drifting through the sea. When they land and metamorphosize into adults, they literally turn inside out, bringing out their spiny adult forms. Once they reach adulthood, sea urchins can actually live for centuries.

Let's get up close and personal with spiny urchins:

Read more on the KQED Science blog, including a few cool animated GIFs!