We have dwarfism...
So why not GIANTISM?

The lion will look like the opposite of a dwarf. It would be HUGE!
I also have come up with flavor text:

Cub:
__ accidentally toppled over another cub! Must be the size difference.

Other cubs seem to be running away from ___ because of (Insert pronoun here) size.
6+ months:

___ Was having trouble getting into (Insert pronoun here) sleeping spot. ___ Has grown too big to fit.

Cub training only:

While training, ___ knocked you down during wrestling! You gave (Pronoun here) an impressed gaze.

Sadly, ___ is too big to be stealthy. The prey noticed (Pronoun) trying to hide in the bushes. Oh well...

___ Did impeccably! The mouse was supposed to live But got crushed by (pronoun) Giant paws. At least (pronoun) Is good at pouncing.


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GAMEPLAY EFFECTS

Any lion with giantism will be born with high strength stats.

A giant huntress will have higher chances of catching larger prey.
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Anyways, That's all for my idea. If anyone has an idea, I can add it!