SCRATCH him in the loving stuff
...wait, isn't that a sort of "hopeless battle"? because iirc water types are OP against fire types
Neither your starter pokemon nor the rival's starter pokemon know any moves that are of their respective types.
Squirtle doesn't know any water-type moves, so it can't do double damage to he forgetin'.
he forgetin' only knows normal type moves, so it won't do half-damage to squirtle.
They only know a basic normal type attack move, and one status changing move.
Squirtle and Bulbasaur have Tackle, while Charmander has Scratch.
Squirtle has Tail Whip (which reduces opponent's defence), while Bulbasaur and Charmander have Growl (which reduces opponent's attack).
Since Growl will reduce Rattata's attack, we're not going to use it.
That just means we know he's gonna hit us and we're scared.
Show him what our claws are made of. Teach him what it means to be in the top percentage.