Last time, on A Pokémon Trainer Is You:

How do you approach your first battle?
– Play it safe and wear them out with Leech Seed

You’re pretty confident you know all the angles here.  You and whatshisname are both using Pokémon you just met, and won’t be able to try any funny business.  Squirtle is tougher than Bulbasaur thanks to its shell that it can hide inside at will, so if they have any sense they’ll try to outlast your Grass attacks and then counterattack with a shell slam or something.  But there’s an easy way to keep that from working…

At your order, the bulb on your Pokémon’s back pulses and fires a single glowing yellow seed that arcs through the air towards Squirtle.  The turtle Pokémon reacts instantly by dropping to the floor and pulling its head and all its limbs into its shell, quick as you can blink, but that won’t stop a Leech Seed.  It hits Squirtle’s shell, sticks, and immediately sprouts a web of green that grows with supernatural speed, climbing around and into the shell.  The other guy is pretty shaken; you don’t think he’s actually seen this attack before.  He manages to call counterattacks, and Squirtle is able to fire Bubbles that knock your Bulbasaur off its feet, but it’s no good.  Water attacks deal only superficial damage to Grass-types, the Leech Seed is gradually sapping Squirtle’s strength, and all Bulbasaur has to do is use its vines to parry attacks and occasionally lash out whenever Squirtle emerges from its shell for too long.  Eventually, Squirtle sinks to its knees, too weak to go on attacking, and Professor Oak calls an end to the battle.