can't say any of the creatures would be real even if Sci-Fi were real, except maybe Duck Bodgers (oops! That's Buck Rogers).
There's an outside chance the stuff in Star Trek could be real enough, since there was some actual science behind it, like in the transporters (The Heisenberg compensators for the Heisenburg Uncertainty Principle) and warp drive (scientists knew about antimatter for a while now), for example.
Hm. Sounds like you'd love having a pet octopus, then. Go down to the local pet store and see if they have any, with an aquarium large enough to put one in. Then instead of having pages eat people's brains, you can throw unruly people in the aquarium with your pet and have it eat their brains. LOL