Drum shrimp, also known as gun shrimp, card shrimp and hairtail shrimp, is called gaba shrimp in the field of diet. It is muddy green, with a prawn claw, one large and one small, about 5 cm long, but its giant claw can reach 2.5 cm long. Gaba shrimp sneaks in the shallow waters of tropical oceans. When the Gaba shrimp hunts, it will quickly close its paws and spray water at a speed of about 100 km per hour, which will shock, stun or even kill prey such as small fish and crabs. This high-speed water flow will cause cavitation and form tiny low-pressure bubbles. When the water pressure returns to normal, the bubbles will burst and make a crackling sound, hence the name "shrimp bump". If a group of shrimps close their paws at the same time, the sound is enough for the submarine to avoid being tracked by sonar detectors.