Mimikyu is one of the most popular and perhaps most mysterious Pokemon. The reason for this mystery is because no one has seen what his real face looks like and the reason why it hates Pikachu so much. Through the years, a lot of theories have risen regarding Mimikyu's true identity and origin. The latest to hit the Pokemon community says that Mimikyu is a clefairy.
Reddit user PoeTeiToe was the one who suggested that Mimikyu was a Clefairy, the original Pokemon mascot. However, due to Pikachu's popularity, Clefairy was toppled from top spot and Pikachu became the official mascot of the franchise. Pikachu was well-received and had the Clefairy not made an appearance in another Pokemon anime or games, it would be completely forgotten.
The Clefairy might be cute and regarded as a pet but it is not immune to feelings of jealousy, hatred, and rage, especially to the one which took its rightful place. Imagine having to live under someone else's shadow all your life. Thus, the Clefairy wanted to regain that lost attention by taking its hatred over a Pikachu doll. Then, when the doll got so damaged, it realized it can use the ragged doll and pretend to be Pikachu.
When it had found a trainer and he tries to lift the disguise, he was afflicted with a mysterious illness Mimikyu is a ghost/fairy type, which oftentimes bring afflictions to people ranging from mild maladies to serious illness.
Why didn't Mimikyu want to be discovered? That's because it is afraid that if its trainer discovered it's a Clefairy, it will abandon him once more. So, it is protecting itself from rejection.
This new theory about Mimikyu seemed more plausible than Mimikyu being Polygorn because the latter is man-made. What do you think? Is Mimikyu more possibly be a Clefairy or Polygorn.