What it does
Wacan Berry triggers automatically when the holder takes super-effective Electric-type damage, halving it, then is consumed. Only fires on super-effective Electric moves.
Electric hits Flying and Water for super-effective damage. Rain teams are one of the strongest archetypes in doubles right now, and their cores are almost entirely Water and Flying types — exactly what Electric counters. Thunderbolt is always on the table; Thunder hits 100% accuracy in rain, meaning the moment you set up weather, you're inviting a perfect-accuracy Electric move aimed at your whole team. Wacan Berry is the cushion that keeps your rain core on the field long enough to matter.
Who runs it
Gyarados (11% of sets) is the main user. Water/Flying means a 4× Electric weakness — in rain, it's the primary target for any opponent running Electric coverage. The berry turns a would-be one-shot into something it can actually survive. Politoed (2%) and Pelipper (2%) are rain setters; if they go down early, your rain team loses its weather. Occasionally they carry the berry to survive a targeted Electric move. Blastoise (3%), Empoleon (2%), and Araquanid (1%) cover the Water side. Corviknight (2%) is Steel/Flying and resists Electric naturally — the berry appearing at 2% suggests a very targeted use case against specific Electric threats.
How to use it
The core application is rain vs. Electric answer. When you're running rain and you expect Electric counter-play, equip Wacan Berry on your most vulnerable Water type. Gyarados with a 4× weakness is the obvious choice — it hits hard enough to justify keeping it on the field, and the berry is the difference between surviving a Thunder and not.
Thunder under rain is 100% accurate. There's no dodging it through accuracy drop mechanics once rain is up. Knowing exactly when it's coming lets you decide: Protect through it, pivot out, or stand in with the berry.
Tips & strategy
Berry value is matchup-dependent. Against a team with no Electric types, you carried a dead item. That's the berry trade-off — you're betting on the opponent's structure. The payoff when it fires is real: Gyarados with solid HP bulk leaves the berry trigger with a meaningful HP total, not 1, and can keep attacking or pivot out on the following turn.