Sea cucumber crawls by stretching its muscles and can only advance four meters per hour.

Barracuda can swim dozens of kilometers per hour, and when attacking other animals, it is faster than ordinary trains.

Squid and octopus can suddenly spray water forward and use the reverse thrust of water to quickly retreat.

Some shellfish can't move by themselves, but they can travel long distances under the boat for free.

There are also some deep-water fish, which have their own luminous organs and swim like twinkling stars.