Never really understood for the eternal bouncing for Spoink with it's tail. Twitching sure to keep it muscles going but it has to rest at some point and if a trainer or child would pick it up ... instant death since it's tail could no longer bounce it's weight ... nope, changing it to twitch it's tail instead.
It can push, bounce away opponent tho with the help of the tail when using it as a spring against the other pokemons body.
I removed it's front legs to give it lower legs to help it moving around and ears to clamp the pearl in place instead.

Grumpig, more center weight and also pushing it's lower part of the legs to act more like feet, to keep balance. Tail has lost the screw pattern or twirl for the balance purpose.
Arms are more fuzzy to act as defense when in close combat, to absorb impact.

Might add more information at some point

• I am trying to go through pokemon ... that I didnt really like because of their design