The snapping claws of male amphipods—tiny, shrimplike crustaceans—are among the fastest and most energetic of any life on Earth. Researchers reporting in the journal Current Biology on February 8 find that the crustaceans can repeatedly close their claws in less than 0.01% of a second, generating high-energy water jets and audible pops. The snapping claws are so fast, they almost defy the laws of physics.