You'd been killed.

You, Ash, Pikachu, Misty, and Brock had gone to fight a new, super powerful Pokémon, and it had killed you.

You were surprised that Arceus had thought you worthy of being revived—just not in the way you expected.

When Arceus had revived you, you'd been revived as a Pokémon!

Now, you have to try and fight Ash, Misty, and Brock again and somehow tell them it's you without getting caught or captured by a human—especially Team Rocket—or killed or hurt by another Pokémon.

Well, this'll give you an interesting view on a Pokémon's life.

(OOC: Choose your Pokémon team from before you got Isekai'ed and what Pokémon you got revived as! You can talk to other Pokémon, btw.)