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Its captive orca program has earned it a terrible reputation—and deservedly so—but SeaWorld San Diego surely scores points for a cool time-lapse video it released last week. If you’ve never seen a Japanese spider crab (Macrocheira kaempferi) molting out of its shell, you should definitely check it out.

“It’s a perfectly natural occurrence for a spider crab,” says Aquarium Curator Mike Price. Like other crustaceans, a crab doesn’t grow in a linear fashion because it has a hard outer shell—an exoskeleton—and it has to shed its shell in a process called molting. You know, just like spiders do.

This trick involves the crab secreting enzymes that separate its inner body from the hard shell and then developing a thin new shell underneath. When that’s done—a process that can take weeks—the crab is ready to break out of the old shell, which it does by absorbing seawater to swell the spaces within it. What you see in the video is the final step—about six hours condensed into 30 seconds—as the old shell finally falls apart and the “new” crab crawls out.

Spider crabs aren’t arachnids, of course, but arachnophobes might like to know that these crabs are the planet’s largest: They can measure 13 feet across and weigh over 40 pounds. Enjoy the video!