The striped paper bubble slug (Hydatina physis) looks fragile. But it’s built to survive. It carries a thin shell, but never hides inside it. Instead, the shell helps with balance as it crawls over the sand hunting tiny worms. You can find these slugs across warm tropical seas, from the Red Sea to the Pacific. They’re usually gliding slowly at night, like living glass. #seabook #seabookapp | Seabook