>>53291954An important factoid is that Pikachu will not debuff you. But he will regularly remove his own debuffs. This means you can do a six curses with Clodsire unimpeded. Clodsire is immune to or resists all of Pikachu's possible moves, but unless he's Tera Grass with Tera Blast you won't ever be able to do that much damage with Clodsire, but a team of them working together will wear Pikachu down in a reasonable amount of time. Even if you're a non-super effective Tera you will still get a huge damage boost from Terastalizing and using the associated move, eg. Tera Ground Clodsire with 6 curses using Earthquake will take off nearly 10% of Pikachu's health bar after Terastalizing.
All the japs who I've seen joining raids have been using Arboliva and Lurantis. Arboliva gets Grass Terrain set up, Lurantis does Sunny Day and then spams Contrary Leaf Storms. It's an excellent way to actually do damage to Pikachu, with the tradeoff being that Pikachu is still able to kill both of them a bit too easily.