I'm thinking of adding humanoid squid into my world, as an expy of the bloodsuckers from the S.T.A.L.K.E.R. games. These cephaloids somehow fell into our universe from a parallel one (they don't know how it happened either), and have the following attributes:
- Their home environment is mainly inside coastal caves with Earth-like gravity and atmosphere. They primarily live on land, but can stay underwater for up to an hour.
- They have an internal skeleton and lungs similar to humans, but with three fingers/claws instead of four (not including the thumb).
- No sternocleidomastoids for extra creepiness. They can still rotate their head, but with a reduced range of motion compared to a human.
- Average adult height range is 5-6 ft (1.5-1.8 metres); weight ranges from 50-70 kg.
- Their head and mouth resembles that of the European squid, with six tentacles around a beak. The tentacles basically work as extra hands or tools, though their primary use is holding food.
- Their diet is primarily fish, with some algae (e.g. seaweed).
Are these viable on Earth? If not, what would I need to change?