As mentioned in some previous works, im pretty into the bittybones AU right now
(which is an undertale au where you can adopt miniature monsters as pets and companions)
and i made some custom for a person on an undertale discord server im on.

it took awhile to help them figure out what they wanted conceptually, with multiple different variations getting talked about before settling on these two.

they're around 3 and 5 inches tall, and these twos story is that they used to be a part of an illegal labratory that was experimenting on bittys in order to learn more about monsters.
the gaster bittybones got out relatively unscathed, as thanks to its natural talent for the scientific it was more used as an assistant than a test subject, but the monster kid was tested on pretty heavily and still has some pretty messed up physiology cus of it, like how they're often leaking black slime from their eyes.
the mini gaster was responsible for building the monster kid the pair of mechanical wings they're wearing and that is how the two of them escaped.

magic wise, the gaster bitty has a regular set of skeleton bitty powers like bone attacks, blasters, teleportation, being able to levitate objects, and the gaster ability to make duplicates of their hands.
The goner kid bitty tho is more limited. mostly all they can do is do a dragon-like breath attack made out of black sooty smoke filled with white sparking stars. these stars burst on contact with things, so this magical attack is basically like him blowing soot and firecrackers at people.

If you would like to commission something similar, i would be happy to design you a custom bittybones of your own, and you can check out my commission info for prices