A. Merritt 
Moon Pool [EPUB ebook] 

Scientists unleash a subterranean horror in the South Pacific in this classic adventure by the author of Burn, Witch, Burn! and The Ship of Ishtar.On the island of Ponape, a party of researchers explores the ruins of an ancient civilization. There they discover an entrance to an underground world full of unusual scientific findings, including strange beings . . .The most intelligent among this advanced race created an offspring, an entity known as the Dweller. Over time, it turned toward evil. Now, it occasionally returns to the surface to prey upon men and women . . . to feed. When the group of explorers release the creature from its prison, they unknowingly launch a battle of good versus evil. And there can be only one victor . . .