Blake once had a Triops creature. These animals date back to prehistoric times, and can be purchased as eggs in a state of suspended animation. By addding water, and warmth, you bring them back to life. Then you keep them alive by feeding them brine shrimp.
At one point, they lay eggs in the sand, and soon die. However, you can let the water evaporate, keep the sand for years, and ressurect them once again.