A hybrid between Zergling, Fennic and Lizard.

They're genderless, not having any real genitals or much of internal organs at all.
Due to their size (between small, medium and large) each ling can have a number of slits on their belly, which opens up, letting out a few goo-like tentacles - their main shapeshifting ability.

Everything Fenling eats instantly turns into nutreous substance, so this creature doesn't really have to pee or poop, but instead, they turn their excess into sexual fluids or building it into their body size (a tiny Fenling might grow to enormous sizes if given lots and lots of food without enough excercises).

Personality
Loyal, caring and protective towards their Master.
They will never abandon or harm the one they've been imprinted to.
If their Master doesn't share their affection, doesn't give them love and good treatment in return to their loyalty and love, a Fenling might get sick and then die.
Likes/Dislikes
Likes: Master and whatever their Master likes. Giving\receiving love and affection. Being useful to their Master.

Dislikes: Anything that threatens their Master and whatever their Master doesn't like. Being abandoned and unloved. Being treated poorly.
Background/History
A hybrid species that been created in a Neksus Labs Inc, mainly as a life-companion.

This species were based on Zerglings from the Swarm itself for being loyal to their Master, having a Hive Mind, high regeneration and ability to mutate under the Master's will.

After a number of experiments with Zergling's genome, a new hybrid was formed, with added features of a: Fennic - for a cuter look, and a Lizard - for a smoother and blexible body.

A creature is now fully loyal to its Master (not Creator), because after seeing them for a first time, Fenling imprints an image of the person in their mind, crating a Link between them. After that Fenling rarely survives if anything fatal happens to their Master.

Lings are made to be Life-companions, meaning they will stay by their Master's side no matter what and will do everything they can and must to protect them and given their ability to mutate and transform - they really can.

Fenlings are best Pets and Companions ever. Best Lovers too.
If you're their Master - they will do what ever you wish and desire to please you.
Their flexible bodies and ability to shapeshift with time into nearly anything you want (not loosing their base form too much).