Ophie
Salingerian Phony
I always check on those weakness but its like Gamefreak doesn't let them work in raids.
It took 2 tries but even my lvl 65 sandaconda did struggle hard against manectric but i beat him.
Damn i hate the absurd defense these raid bosses get. and the fact that most ai assistant trainers use weak pokemon or terrible movesets.
Also nearly lost against a quite powerful Frosmoth which had the Shield Dust ability which prevents additional effects made by attacks. But beloved level 100 Incineroar pulled through. That Frosmoth was eating special attacks like candy but couldn't handle physical attacks.
If this is a 5-star Max Raid Battle for Manectric, then that Manectric will be at Level 60. If your Pokémon are Level 65, assuming you've completed the game, the AI partners will be around Level 40 to Level 50, meaning they'll be pretty weak and ineffectual against them (unless you have Isle of Armor and get lucky and get Avery or Klara as a partner, whose Slowbro will be the same level as the Pokémon you bring in). I suggest you bring in something higher-leveled or level up your Pokémon with EXP Candies.
Bear in mind, however, that even at Level 100, any computer player partner who isn't Avery or Klara will still be at Level 70. Since they have no Effort Points, they'll be able to take a hit, but you will still have to do the heavy lifting.
So it's not in the Isle of Armor Dex, but it's catchable in Raid Battles there? Interesting.
Indeed, there are a lot of Pokémon not in the Armor Pokédex you can find Hidden Abilities for in the Isle of Armor anyway. Another example is Bulletproof Dubwool. After a couple of weeks, I was able to find and nab one.