Sea Urchin: Sea urchins do not usually look like a spiky ball when they are first born. To gain that shape, they must go through several steps in reproduction as well as growth. Much like the Sand Dollars, Sea urchins also use a process called spawning to find a mate. Both the male and female will release their sexual gametes into the water until each fertilizes the other. The two sea urchins will never meet or reproduce together, they just simply lay their eggs or release their sperm than move on.