Pokémon Mystery Dungeon: Blue Rescue Team and Red Rescue Team/Mt. Steel

Boss Battle: Skarmory
This is the very first boss you have fought yet, and will undoubtedly be the toughest foe you have faced yet. Since his type is Steel/Flying, Cyndaquil, Charmander, and Torchic will have it much easier than the rest. If you picked a Grass type, you had better have a strong Fire type team mate to deal out the damage.

After Skarmory falls, he will fly off, giving you access to the Magnemite pair. After saving them, you will warp back out of the dungeon, and meet the greatly relieved friend. Before you head back to your base, one of the Magnemite joins your rescue team, but the other two decide against it, but still offer their undying gratitude and support.