I could never remember, since when I was a kid, for some reason I always played solo with my starter, using other pokémon only for HMs or for switching in and using revives/potions on my starter. So, it must be the pokémon I caught to teach cut to. No, no, I must have caught one before, to switch in for potions for the first gyms. Well, anyway. Even today, I catch very few pokémon, most times only my team (made up of four pokémon) and HM helpers. Mainly because I'm lazy (complete the pokédex!? Do it yourself, Oak!), and also because I don't like catching pokémon just to put them on boxes. Pixels have feelings, too.