Basilisk

Basilisks are a species of snake who live in the desert. They've grown to legendary status over the years, and no one has seen one for eons. They remain in myth as monstrous creatures who swim under the sand and their gaze turns anyone who looks at them into sand. Their fangs drip venom, and one drop is enough to kill an entire army. Often times, people sell bones claiming that they're the fangs and spine of a dead basilisk, and that the bones still hold magical properties. The reality, of course, is less exciting. The snakes were real and grew to considerable size. They were big enough to eat people, but they did so rarely and usually out of desperation. Their eyes glowed in the moonlight, and they were nocturnal when the temperatures were less severe. They had a venomous bite which is how they hunted and tended to prey on desert antelopes and anything else they could eat. They had a lifespan of twenty years. Basilisks had scales above the eyes that looked like horns. Most snakes were brown with darker patterns along their back. They lay eggs in burrows and caves which they steal from other animals. The newly hatched snakes are very small compared to the adults, and they remain in the nest for a month before venturing out on their own. Basilisks are magical creatures, and even shed skins have heat resistant properties. Their blood has magic poison properties, and their venom can be harvested without killing the snake. Basilisk bone powder is rumored to give people visions and foresight. Whether any of this is true is still up for debate, but common belief is that the properties are true. Basilisks are largely independent creatures. Males and females look the same, and it's rare for them to come across one another. No one knows exactly why they died out. Some believe that they all returned to another plane of existence. Others blame over hunting of the snake for their properties. A third group believes there was an argument between the gods, and the snakes were wiped out in the course of that conflict. And yet a fourth group believe that the snakes never went extinct and are still living in the desert out where no one would dare go and are still alive and well.