Echinodermata

This may come as no surprise: “The starfish does not have the capacity to plan its actions.” Instead, its rudimentary nervous system simply allows for the leg with the strongest stimulus to move the whole creature toward the nearest food source. Starfish evolved from bilateral ancestors, but they only grow out certain parts. Wikipedia explains this better and funnier than I could ever could: “Mapping the expression patterns of genes that express differently across the body axes suggests that one could think of the body of a starfish as a disembodied head walking about the sea floor on its lips.”