Breccia en las Montañas de la Locura

We had expected, upon looking back, to see a terrible and incredible moving entity if the mists were thin enough; but of that entity we had formed a clear idea. What we did see - for the mists were indeed all too maliguly thinned - was something altogether different, and immeasurably more hideous and detestable. It was the utter, objective embodiment of the fantastic novelist’s "thing that should not be"; and its nearest comprehensible analogue is a vast, onrushing subway train as one sees it from a station platform - the great black front looming colossally out of infinite subterranean distance, constellated with strangely colored lights and filling the prodigious burrow as a piston fills a cylinder.

Enrique Breccia y HPLovecraft, At The Mountains Of Madness (Gracias, doctor)