Espeon is one of the 8 possible evolutions for Eevee. To get one, Eevee’s friendship has to be at least 220. Once that is true, if you level it up during the day, you will get an Espeon. Alternatively, if you’re lazy, they can appear in SOS calls from Eevee during the daytime. They appear about 5% of the time. But how good is Espeon?
There’s not much special about Espeon at first glance. It’s a pure Psychic type, and it gets Synchronize as its regular ability, which other pure Psychic types like Beheeyem and Musharna also get. However, something unique about this Pokemon is its hidden ability: Magic Bounce. Only 5 other Pokemon get this ability, 3 of which are Mega Evolutions (Absol, Sableye, and Diancie). The other 2 are Natu and Xatu, which you can’t find in Sun/Moon anyway. So, if your opponent’s strategy is to inflict status conditions or set up entry hazards, then this Eeveelution would be a good fit for you. However, getting hidden abilities in Sun/Moon is a pain in the neck because they are only available through SOS chaining. You have to have at least a chain of 10 for a 5% chance to get a hidden ability. At 20, you have 10%, and at 30%, you max out at 15%. Getting a hidden ability Espeon is against your odds, so it might be best to just wait for a hidden ability Eevee instead. A good way to verify that an Eevee does in fact have its hidden ability is to have your lead Pokemon have at least one Fighting type move. Eevee’s hidden ability is Anticipation, which just alerts the trainer that the Pokemon they’re facing has a super effective move. Since it’s a Normal type, if it has its hidden ability and you have a Fighting move, it will activate. Otherwise, it will be difficult to tell. If you get an Espeon and you’re unsure if it has its hidden ability, use a status move on it. If it gets reflected back at you, then it is hidden ability. If it just gets affected by the status condition, then it has Synchronize. It’d be best to use a move where the status condition inflicted won’t affect you. Bringing a Poison type and teaching it a Fighting type move would be a good idea, although running into an Espeon might be a problem, since Psychic is super effective against Poison. Luckily, Alola Muk can learn Brick Break, a Fighting type move, and it’s a Poison and Dark type. This means a Toxic from this Pokemon will always land and it won’t affect it if Synchronize is activated and it doesn’t take damage from Psychic type moves under most circumstances.