When hundreds of crocs are found dead along Australia's Victoria River, scientists are baffled. Could a toxic toad be the source of this massacre? And in Morocco, Nat Geo WILD recounts the awe-inspiring birth by a mule. The offspring, born from the union of a male donkey and a female mule, shatters beliefs that female mules are infertile. And along the U.S.'s West Coast, more than a dozen sharks are found dead. Could a red tide be responsible, or is something more sinister to blame?