Generation Iii
Shield Dust
Prevents added effects.
Detailed Effect
This Pokémon is immune to the extra effects of moves used against it. An extra effect is a move's chance, listed as an "effect chance", to inflict a status ailment, cause a stat change, or make the target flinch in addition to the move's main effect. For example, Thunder Shock's paralysis is an extra effect, but Thunder Wave's is not, nor are Knock Off's item removal and Air Cutter's increased critical hit rate.
Pokémon With Shield Dust
12 canonical Pokémon forms can have this Ability.

Caterpie
Weedle
Venomoth
Wurmple
Dustox
Scatterbug
Vivillon
Cutiefly
Ribombee
Snom
Frosmoth
Ribombee Totem