There are many organisms that are extinct, meaning they no longer exist on Earth. It's impossible to name just one, as there are literally thousands of extinct species.

Here are a few examples:

* Dinosaurs: This group of reptiles went extinct about 66 million years ago.

* Dodo: This flightless bird was native to Mauritius and went extinct in the 17th century due to human activity.

* Passenger Pigeon: This was once the most abundant bird in North America, but became extinct in the early 20th century due to hunting and habitat loss.

* Woolly Mammoth: This iconic ice age mammal went extinct around 10,000 years ago.

* Tasmanian Tiger: This marsupial predator, native to Tasmania, became extinct in the 20th century.

These are just a few examples. There are countless other extinct organisms, each with a unique story of how they disappeared from the Earth.