This is Applin
Or, should I say the green wormy behind it is Applin
It's like a little slug burrowed in the back and it squirms about all weird.
In Sword you do a really easy sidequest to receive a special item to evolve it into a Flapple.
Yes, it's using pieces of apple as wings, the adorable little slug weirdo. In Shield you get a different item, which gives you Appletun
Half Dragon, Half Apple pie. Wild.