Answer: Because due to its characteristics he could not find one single word to describe it.
Step-by-step explanation:
In his novel published in the year of 1898 called "The War of the Worlds" the author H.G. Wells described the martians as creatures, and the martian spacecraft as something with tentacles and a heat-ray and a tube-gun to be a "thing". In Chapter 10 H. G. Wells first describes the fighting machines as it quotes: "And this Thing I saw! How can I describe it? A monstrous tripod, higher than many houses, striding over the young pine trees, and smashing them aside in its career; a walking engine of glittering metal, striding now across the heather; articulate ropes of steel dangling from it, and the clattering tumult of its passage mingling with the riot of the thunder."