Can you help me find a movie with a vague description?
Of course! I'll do my best to help you find a movie based on a vague description. Please provide me with the details you remember about the movie, even if they are not very specific or clear.
I remember it being a sci-fi fantasy comedy where friends used a book to summon what I can only describe as water demons or sea monsters, they were nerds or something living in an apartment. It all started with one of them explaining how the book was evil, or coming true. I'm sorry, but that's all I can remember.
Based on the description you provided, it sounds like the movie you are referring to could be "The Cabin in the Woods" (2012). Although it is primarily a horror-comedy rather than a true sci-fi fantasy, it does involve a group of friends who venture into a remote cabin and accidentally summon creatures according to the instructions in an ancient book. The characters in the film are also somewhat nerdy, and the story revolves around the idea of an evil force or ritual coming true. However, please note that this is just a suggestion based on the details you provided. If it's not the correct movie, feel free to provide any additional information you remember.
Well, I remember one of the creatures in the movie having a suction cup type face like an octopus, and the main villain of the book being an aquatic demon from the sea.
Based on the additional details you provided, the movie you are referring to could be "The Monster Squad" (1987).
In this film, a group of friends, who are self-proclaimed "monster nerds," discover an ancient book that contains instructions for summoning monsters. One of the creatures they encounter is indeed a sea creature with a suction cup-like face, resembling an octopus. As the story progresses, the main villain of the book, Count Dracula, strives to dominate the world with the help of other classic monsters such as Frankenstein's Monster, the Wolfman, and the Mummy.
Please let me know if this suggestion matches the movie you are thinking of!