the.com/echinoderm
Sea creatures with five-fold symmetry and a hydraulic plumbing system instead of blood.
means A marine animal like a starfish, sea urchin, or sea cucumber, built on a five-part radial body plan with spiny skin.
from From Greek echinos (hedgehog) plus derma (skin), literally hedgehog-skin, coined for the prickly urchins that started it all.
Water powerMove via water-filled tube feet, no muscles needed.
BrainlessThey have no brain whatsoever, just nerve rings.
Regrow limbsSome starfish regenerate a whole body from one arm.
Symmetry switchLarvae are bilateral; adults rebuild into fivefold radial.