Mimikyu, the Disguise Pokemon, is a new Pokemon released in Sun and Moon. It was another “Pikachu” for the generation, the other being Togedemaru. It is a Ghost/Fairy type, which is unique. This means it has 3 immunities, and is only weak to Steel and Ghost. Although it would seem like Aegislash would be a good Pokemon to use against it, Aegislash would be weak to Mimikyu’s Ghost type moves, so stick to using a Steel type. As for a secondary type, you could either double up on your resistance to Fairy by also being a Fire type (Heatran is the only Fire/Steel type) or you could add on a Dark type to resist Ghost moves (Pawniard and Bisharp are the only Steel/Dark types). However, both of these Pokemon are flawed. Something else unique about Mimikyu is its ability, Disguise. It basically acts as a Substitute without taking away any of the Pokemon’s health. However, this is only for direct damage. Weather, hazards, burns, and poisons will still deal damage, but they will not break the Disguise. Hitting Mimikyu with any direct move will break its Disguise, but Mimikyu will not take any damage regardless of how much damage the move would have done had its Disguise already been broken. Unlike Substitute, there’s no way to recover the Disguise. Once it’s broken, it’s gone until the match is done. Still, this gives Mimikyu an inherent advantage over you: it basically gets a free move. There are a few ways to prevent it from using its free move.
Although Mimikyu is fast, it can be outsped. Using any sort of move that deals damage and could cause Mimikyu to be unable to move would be good. Although freezing or paralysis could do this, both of those are flawed. Freezing only has about a 10% on most moves. Paralysis, although there is a move that can cause 100% of the time, there’s only a 25% chance that Mimikyu will be unable to move. Flinching would be your best option. Fake Out would be a good move, but because of Mimikyu’s Ghost typing, you could only pull this off if you had a Scrappy Kangaskhan. There is a better option that does not rely as much on luck or planning.
The ability Mold Breaker nullifies some abilities. Although this is the only effect, it could potentially remove an advantage your opponent has over you. Although it doesn’t affect all abilities, it does affect Disguise. Remember the typings I talked about earlier? Our ideal Pokemon would at least be Steel type and have Mold Breaker. Luckily, there is one Pokemon that meets that criteria: Excadrill. Although Drilbur and Excadrill are not available in Sun/Moon (or Ultra Sun and Ultra Moon to our knowledge) and Mold Breaker is its hidden ability, it is not too difficult to get.