Creature Suggestion : Critters (From movies of the same name)
It doesn't really fit any other creature of the mod but since this is the only mod that accepts any request in its description and this Sci-Fi creature doesn't exist on the worshop, I propose it.

Appearence / Description : Wiki [en.wikipedia.org]
Size : Big Cat like
Weight : Cat like ?
Move Speed : A little faster than a human (5 c/s Maybe)
Diet : Any Organique life
Hunger : Always*
Temp. Range : Maybe -30ºC +30ºC
Life Expectancy : Unknown
Wildness : 100% (untameable)
DPS : Really a lot
Armor/Life : If we refer to the movies, extremely weak
Dangerousness : Much for the Neolithic but less for the others

Characteristics* :
- Always Agressive
- Eat their target alive
- Can project spikes that confuse the target
- Lays eggs very often but have a very long incubation time (2-6 eggs - 30 days) & Born adult
- Have the ability to group together to form a giant man-eating mass **
- Weakness to explosives
- Strangely highly inflammable (Blood maybe)
- Have sticky blue blood and really a lot of teeth (And love fast food, more than human )

* : Interesting gameplay mechanics (If possible)
- Always Agressive : Attacks everything (In the movies they also have the "intelligence" to destroy the doors and to cut the electricity.)
- Hunger : Make sure that they are never full and are always looking for food (Maybe a stats bonus compensating for the malus given by the hungry state)
- Spikes : Secondary attack often used on opponents tougher than themselves, confuses the target and can knock them unconscious in high doses. (Maybe make it harvestable to make a weapon or a drug, or something else)
- Eggs Laying (Inedible) : Make sure that when they arrive on the map, lays at least once if there are no Critters's eggs on it. Make sure that they lay their eggs in a dark place away from the colony (in mountain caves for example). If we refer to the movies, Critters born adult.

** : A mechanic that I don't think is feasible, maybe make another creature. If you are already doing the basic one I would be very happy, but if you are interested in the other one, I can make some assumptions about its characteristics. (It compared to the basic Critters would be really dangerous, for everyone)

Ps : I used automatic translation machine, of which there may be some sentence malformation and mistakes.