Weak Armor
Raises Speed and lowers Defense by one stage each upon being hit by a physical move.
Full effect
Whenever a physical move hits this Pokémon, its Speed rises one stage and its Defense falls one stage. This ability triggers on every hit of a multiple-hit move.
In-game description
The Pokémon's Defense stat is lowered when it takes damage from physical moves, but its Speed stat is sharply boosted.
Stats
Regular ability (6 Pokémon)
Hidden ability (17 Pokémon)
Only available through specific encounters (Dynamax Adventures, Tera Raids, hidden grottoes, etc.).