You're probably thinking of how to defeat the fifth gym leader, Flannery.
Here's some advice:
Flannery's Team:
* Torkoal (Level 27) - Fire type
* Slugma (Level 24) - Fire type
* Magcargo (Level 27) - Fire/Rock type
* Numel (Level 25) - Fire/Ground type
Strategies:
* Water types are your best friend! Pokemon like Squirtle, Wartortle, Blastoise, or even a strong Poliwhirl will be very effective against Flannery's team.
* Rock types are also good. Onix or Geodude can hit hard against her fire types, but watch out for Magcargo.
* Consider using Ground-type moves. Moves like Earthquake or Dig can hit hard against her Fire-types.
* Be wary of her Torkoal's Shell Smash. This move will greatly boost her attack and speed, making it very dangerous. If possible, try to take it out early.
* Use potions and revives! It's important to keep your team healthy throughout the battle.
Some Pokemon suggestions:
* Squirtle/Wartortle/Blastoise: Water Gun, Bubble Beam, Ice Beam
* Onix/Steelix: Rock Throw, Rock Slide, Earthquake
* Geodude/Graveler/Golem: Rock Throw, Rock Slide, Earthquake
* Poliwhirl/Poliwrath: Bubble Beam, Surf, Ice Beam
Remember to train up your Pokemon before taking on Flannery! She's a tough opponent, but with the right strategy and some well-trained Pokemon, you can definitely defeat her.