Your memories of catching your first legendary Pokémon will begin way before you throw that Pokéball. It all starts with remembering (or not) to save your game before you jump into battle. Failure to do so would mean you had one chance to get it right, or face turning your game off and spending a ton of time getting to it again.
When you finally did find one of the legendary bird Pokémon or maybe Mewtwo himself, that was where the tension began. You started to overthink every attack in case it ends up making the Pokémon faint. Once you finally whittled it down to its last sliver of health, the barrage of Pokéballs began. One had got to work eventually. Surely enough, it clicked. You’re now the proud trainer of a one-of-a-kind Pokémon and an incredibly powerful one at that. Now you just gotta test it out.