Snorkelers in mangrove forest waters inhabited by the upside-down jellyfish Cassiopea xamachana report discomfort due to a sensation known as ‘stinging water.’ When Tohoku University’s Dr. Cheryl Ames and colleagues looked at toxin-filled mucus the jellyfish release into the water, they were surprised to discover gyrating balls of stinging cells — dubbed cassiosomes — inside the mucus. Cassiopea xamachana medusae (5-12 cm in diameter)...
