Thanks to this thread, I decided to check out my Pokemon in D/P. It turns out my last save was in the middle of a Battle Tower series, and I had to fight a Dragon Tamer guy in a dual battle.
He had Aerodactyl, Feraligatr, Typhlosion, and Steelix. I had TTaur, Aerodactyl, PorygonZ, and Cradily. I barely managed to win thanks to Grass Knot on his Steelix.