(i read on bulbapedia that bulbasaur’s “bulb” might be an onion, so that inspired this)
Abilities: Moody and I cri evri tiem (takes a turn every other turn to cry)
One day, a Bulbasaur was born with a birth defect where it had a complete lack of chlorophyll in the bulb. No one would mate with it because it looked different.
Then one day, it wandered into an onion farm. Then, some random dude abducted him out of his backyard, mistaking him for one of his onion plants.
The dude took him inside, and cut his back, still mistaking it for an onion. The knife got lodged in its bulb, and it was unable to get it out.
It is unknown how the entire species adopted a knife in their bulb, but it is suspected that its anatomy recognized it as another limb, and thus it can use it as so. The knife causes them tremendous pain nonetheless, and they are unable to get it out because it is a part of their anatomy.