As a kid I read a book that was a collection of scary / sci-fi short stories. One involved a blob-like creature from the ocean depths, somehow disturbed or cast up onto the beach. It feared light (naturally), hid in the dark, and went around at night sucking up various people. One scene had some guy keeping it at bay with a campfire... until he ran out of wood. In the end, the creature tried to get back to the ocean but, by then, the authorities were looking for it. A soldier killed it with a flame-thrower on the beach, just before it escaped.
One involved a blob-like creature from the ocean depths,
IT WAS A GREAT GRAY-BLACK HOOD OF HORROR MOVING over the floor of the sea. It slid through the soft ooze like a monstrous mantle of slime obscenely animated with questing life. It was by turns viscid and fluid. At times it flattened out and flowed through the carpet of mud like an inky pool; occasionally it paused, seeming to shrink in upon itself, and reared up out of the ooze until it resembled an irregular cone or a gigantic hood. Although it possessed no eyes, it had a marvelously developed sense of touch, and it possessed a sensitivity to minute vibrations which was almost akin to telepathy. It was plastic, essentially shapeless. It could shoot out long tentacles, until it bore a resemblance to a nightmare squid or a huge starfish; it could retract itself into a round flattened disk, or squeeze into an irregular hunched shape so that it looked like a black boulder sunk on the bottom of the sea.
somehow disturbed or cast up onto the beach.
Had it not been for a vast volcanic upheaval on the bottom of the ocean basin, the black horror would have crept out its entire existence on the silent sea ooze without ever manifesting its hideous powers to mankind.
Fate, in the form of a violent subterranean explosion, covering huge areas of the ocean's floor, hurled it out of its black slime world and sent it spinning toward the surface.
It feared light (naturally), hid in the dark, and went around at night sucking up various people. One scene had some guy keeping it at bay with a campfire... until he ran out of wood.
He stood frozen in absolute helpless panic as the tiny fire smoldered down into darkness.
At the last instant, a charred bit of wood broke apart, sending up a few sparks, and in that flicker of final light he glimpsed the horror.
It had already glided out of the bushes and now it rushed across the small clearing with nightmare speed. It was a final incarnation of all the fears, shuddering apprehensions and bad dreams which Henry Hossing had ever known in his life. It was a fiend from the pit of Hell come to claim him at last.
A terrible ringing scream burst from his throat, but it was smothered before it was finished as the black shape of slime fastened upon him with irresistible force.
In the end, the creature tried to get back to the ocean but, by then, the authorities were looking for it.
A number of helicopters which had hovered over the area during the afternoon landed on the strip of shore, bringing food and supplies. At Chief Underbeck's insistence, barriers were set up on the beach. Guards were stationed along the entire length of the highway; powerful searchlights were brought up. Another truck from Camp Evans arrived with a portable machine gun and several flame-throwers.
By eleven o'clock that night, the stage was set. The beach barriers were in place, guards were at station, and huge searchlights, erected near the highway, swept the dismal marsh with probing cones of light.
At eleven-fifteen the night patrols, each consisting of ten strongly armed men, struck into the swamp again.
A soldier killed it with a flame-thrower on the beach, just before it escaped.
There was a collective gasp of horrified dismay as the monster, with a quick forward lurch, squeezed through the barrier. It tilted there briefly, twisting, as if a few last threads of itself might still be entangled in the wire.
As it moved to disengage itself and rush down the wet sands into the black sea, one of the guards hurled himself forward until he was almost abreast of the barrier. Sliding to his knees, he aimed at the escaping hood of horror.
A second later a great searing spout of flame shot from his weapon and burst in a smoky red blossom against the thing on the opposite side of the wire.
Black oily smoke billowed into the night. A ghastly stench flowed over the beach. The guards saw a flaming mass of horror grope away from the barrier. The soldier who aimed the flamethrower held it remorselessly steady.
There was a hideous bubbling, hissing sound. Vast gouts of thick, greasy smoke swirled into the night air. The indescribable stench became almost unbearable.
When the soldier finally shut off the flamethrower, there was nothing in sight except the white-hot glowing wires of the barrier and a big patch of blackened sand.
With good reason the mantle of slime had hated light, for its ultimate source was fire–the final unknown enemy which even the black hood could not drag down and devour.
Unfortunately it has appeared in a large number of collections, so without more details I can't identify which particular "book that was a collection of scary / sci-fi short stories" you might have read it in. I personally read it in "Alfred Hitchcock's Monster Museum: Twelve Shuddery Stories for Daring Young Readers". This collection also included a great story about a scientist who attempts to surgically repair a malformation in the heart of an alligator and inadvertently recreates dragons ("The Day of the Dragon", by Guy Endore), and another famous short story called "The man who sold rope to the gnoles". Ring any bells?