After Dracula, this is one of the author's most famous horror novels. Set in 19th century England, the story centres around a giant white worm that can transform itself into a human female.
Excerpt:
That afternoon Adam decided to do a little exploring. As he passed through the wood outside the gate of Diana’s Grove, he thought he saw the African’s face for an instant. So he went deeper into the undergrowth, and followed along parallel to the avenue to the house. He was glad that there was no workman or servant about, for he did not care that any of Lady Arabella’s people should find him wandering about her grounds. Taking advantage of the denseness of the trees, he came close to the house and skirted round it. He was repaid for his trouble, for on the far side of the house, close to where the rocky frontage of the cliff fell away, he saw Oolanga crouched behind the irregular trunk of a great oak. The man was so intent on watching someone, or something, that he did not guard against being himself watched. This suited Adam, for he could thus make scrutiny at will.
The thick wood, though the trees were mostly of small girth, threw a heavy shadow, so that the steep declension, in front of which grew the tree behind which the African lurked, was almost in darkness. Adam drew as close as he could, and was amazed to see a patch of light on the ground before him; when he realised what it was, he was determined, more than ever to follow on his quest. The black had a dark lantern in his hand, and was throwing the light down the steep incline. The glare showed a series of stone steps, which ended in a lowlying heavy iron door fixed against the side of the house. All the strange things he had heard from Sir Nathaniel, and all those, little and big, which he had himself noticed, crowded into his mind in a chaotic way. Instinctively he took refuge behind a thick oak stem, and set himself down, to watch what might occur.
After a short time it became apparent that the African was trying to find out what was behind the heavy door. There was no way of looking in, for the door fitted tight into the massive stone slabs. The only opportunity for the entrance of light was through a small hole between the great stones above the door. This hole was too high up to look through from the ground level. Oolanga, having tried standing tiptoe on the highest point near, and holding the lantern as high as he could, threw the light round the edges of the door to see if he could find anywhere a hole or a flaw in the metal through which he could obtain a glimpse. Foiled in this, he brought from the shrubbery a plank, which he leant against the top of the door and then climbed up with great dexterity. This did not bring him near enough to the window-hole to look in, or even to throw the light of the lantern through it, so he climbed down and carried the plank back to the place from which he had got it. Then he concealed himself near the iron door and waited, manifestly with the intent of remaining there till someone came near. Presently Lady Arabella, moving noiselessly through the shade, approached the door. When he saw her close enough to touch it, Oolanga stepped forward from his concealment, and spoke in a whisper, which through the gloom sounded like a hiss.