Mega Aggron sheds its Rock typing and becomes pure Steel — one of the most defensively resilient types in the game. Steel resists 10 types (Normal, Flying, Rock, Bug, Steel, Grass, Psychic, Ice, Dragon, Fairy) and is immune to Poison. The Rock type’s weaknesses (Water, Fighting, Ground, Grass, Steel) are gone. What remains is a Pokémon with only three weaknesses: Fire, Fighting, and Ground.
Filter then reduces all super-effective hits by 25%. A Fighting move that would deal 2× damage now deals 1.5×. Even with three remaining weaknesses, Mega Aggron can survive hits that should KO it.
Physical Defense wall
At 230 base Defense (equal to Mega SteelixMega SteelixmegaSand Force boosts Ground, Rock, and Steel moves by 1.3× in sandstorm — pair with Tyranitar to combine the Sand setter with a devastating Ground attacker.Click to read more →), Mega Aggron is one of the physically hardest-to-KO Pokémon available. Physical attackers need multiple super-effective hits to break through, and Filter softens even those. Head Smash (Rock STABSTABmechanicSame-Type Attack Bonus: a move deals ×1.5 damage when its type matches one of the user's types.Click to read more →… wait, it lost Rock type) — Heavy Slam and Iron Tail are its main attacks, hitting hard with 130 base Attack.
What stops it
- Fire-type special attackers — While Filter reduces damage, special Fire moves from Charizard or Volcarona can still threaten after the reduction.
- Fighting moves — Super-effective but reduced. Conkeldurr or GarchompGarchomppokemonThe premier spread attacker under Tailwind. Earthquake hits both opponents, Scale Shot chains Speed boosts, and Dragon Claw threatens opposing dragons.Click to read more → with coverage moves are the best counters.
- Ground-type moves — Earthquake hits for 2× (reduced to 1.5× by Filter, but still significant). Garchomp’s Earthquake threatens it.