There is the 'Tentacle Monster' story by an indie author. In this story, a small coastal town is terrorized by a tentacle - like sea monster. It starts with fishermen noticing strange disappearances of their catches and then people start to go missing too. The town's people have to figure out how to deal with this unknown and terrifying creature. It's a story full of suspense and horror elements.
Some tentacle monster stories can be found in old - timey pulp fiction magazines. These often had stories where explorers in uncharted territories would encounter tentacle - covered monstrosities. They were usually part of the 'weird fiction' genre, where the tentacle monsters were used to shock and awe the readers, taking them into strange and often terrifying fictional worlds.