Overcoat

Overcoat grants immunity to all damage from weather effects and powder/spore-based moves, introduced in Generation V. The Pokemon takes no damage from Sandstorm or Hail chip damage, providing passive survivability in weather-heavy matchups without requiring a weather-immune typing.

Starting in Generation VI, Overcoat was expanded to also block all powder and spore moves: Spore, Sleep Powder, Stun Spore, Poison Powder, Rage Powder, and Cotton Spore are all completely negated. This dual function -- weather protection plus powder immunity -- makes Overcoat a comprehensive defensive utility ability. The powder immunity is particularly valuable as it provides a reliable check to Spore users like Breloom and Amoonguss, which are otherwise difficult to switch into safely.

With 22 Pokemon carrying this ability, Overcoat appears on a diverse range of Pokemon including Mandibuzz, Forretress, Shelmet line, and several Bug-types. In competitive play, Overcoat Mandibuzz is a notable example -- combined with its natural bulk, Roost, and Defog, it can switch into sand or hail teams without chip damage and ignore Spore-based threats. The ability is functionally similar to Safety Goggles as an item, freeing up the item slot for Pokemon that would otherwise need the goggles for powder protection.