What sea creature looks like seaweed and has a scary name?

The sea creature that resembles seaweed and has a scary name is the "dead man's fingers." This marine organism, a type of soft coral, has a frilly, finger-like appearance that can easily be mistaken for seaweed. Its eerie name is derived from its shape, which can evoke images of skeletal fingers, adding an unsettling aspect to its otherwise fascinating nature.