The starfish may strike you as an odd beast, but mathematically it truly is the most odd creature. Whereas most animals are driven by symmetry and evenness, the starfish stays in the realms of oddness. It has five arms (sometimes seven), one foot, one eye, three kidneys, three mouths, eleven pairs of chromosomes, fifteen nerve rings and there are two hundred and three known species. When a new species was isolated in 2004, experts believed the number had become even, but the 'new' starfish (the Javanese sea star) turned out to be two separate new species, keeping the number odd.
