Tweel (also referred to as a "Tweerl", the exact pronunciation of the word is said to be impossible for humans) is a fictional extraterrestrial from the planet Mars, featured in two short stories by Stanley G. Weinbaum. The alien was featured in "A Martian Odyssey", first published in 1934, and "Valley of Dreams" four months later. Weinbaum died of lung cancer soon after, and a third installment in the series never saw fruition. Tweel remains one of the most recognised aliens in early science fiction, and is said to be an inspiration for aliens in the works of Isaac Asimov and Arthur C. Clarke.