Anode and Cathode

Anode (アノード, Anode) and Cathode (カソード, Cathode) are held items.

An anode raises the Special Attack status of a Pokémon with Minus by 50%. A Pichu holding it while traded would evolve into a Minun.

A cathode raises the Special Attack status of a Pokémon with Plus by 50%. A Pichu holding it while traded would evolve into a Plusle.