Shield Dust is an ability introduced in Generation 3. So far, 10 Pokémon have this ability.
When the Pokémon is damaged by an attack, any additional effects are negated (similar to the attacker having Sheer Force, but without increasing damage). For example, Body Slam would only deal damage and not have its usual 30% chance of causing Paralysis. It does not stop moves that do not cause damage, like Thunder Wave. Shield Dust also prevents poisoning from Poison Touch unless the user of Poison Touch used Sunsteel Strike.
Outside of battle
Shield Dust has no effect outside of battle.
Pokémon with Shield Dust