The extinct dodo
He has existed, the dodo, but he is no longer on this globe.
The dodo is a (or was) a bird, the size of a turkey. He had little, useless wings. His ancestors were pigeons that came to the island of Mauritius. Because there was a lot of food, and no enemies, these pigeons could develop in thousands of years.

But then!
Then (in 1507) people arrived on the island and the people killed all the dodos there. They hunted for the food and the dogs and rats of their ships ate the eggs and also the little dodo chicks.