Generation Iii
Minus
Powers up with PLUS.
Detailed Effect
This Pokémon has 1.5× its Special Attack if any friendly Pokémon has Plus or Minus. This bonus does not count as a stat modifier. If either ability is disabled by Gastro Acid, both lose their effect.
Pokémon With Minus
8 canonical Pokémon forms can have this Ability.

Minun 
Klink
Klang
Klinklang
Toxtricity Low Key
Toxtricity Low Key Gmax
Electrike
Manectric