Echo (Ichythyosaur) is a shark in Hungry shark world which has a special ability to warn you about approaching hazards, mines, evil sharks and more. Its size tier is large.
It has a good high speed around the speed of the mako shark's speed and a good amount of health. The annoying part about this shark is if you are deliberately approaching danger it will warn you and it can be hard to not pay attention to. This shark is the best in the large tier group but can only be unlocked once you have all 3 large sharks and all of them full grown.