There is an unproven theory about how Ditto was originated from a failed experiment to clone Mew, which was the reason why both can use Mimic, but that theory only last for so many generation.

Rathurue said:

There is an unproven theory about how Ditto was originated from a failed experiment to clone Mew, which was the reason why both can use Mimic, but that theory only last for so many generation.

Correction: the move they both share are Transform, Mimic is a diffent move where it copies a single move only.

laisy said:

Correction: the move they both share are Transform, Mimic is a diffent move where it copies a single move only.

Whoops, wrong move. Guess it's time to sleep instead of danbooru browsing then, it's almost Tuesday already...

Rathurue said:

There is an unproven theory about how Ditto was originated from a failed experiment to clone Mew, which was the reason why both can use Mimic, but that theory only last for so many generation.

Well if it was proven, it wouldn't be a theory anymore.