What it does
Cosmic Power raises both Defense and Sp. Def by one stage per use. Both defenses climbing simultaneously means physical and special threats both need to work harder to secure a KO. Stage multipliers go: ×1.0 base → +1 ×1.5 → +2 ×2.0 → +3 ×2.5, up to +6 ×4.0. After even two or three uses, the damage threshold required to KO starts feeling out of reach for standard sets.
The move does nothing offensively — every use is a turn invested into durability, which requires a free window in doubles where two opponents are both pressuring you.
Who runs it
Starmie runs Cosmic Power in roughly 33% of sets. Its high speed means it often sets up before faster threats can threaten it. Natural Cure removes status on switch-out, protecting the setup strategy from Burn or Poison. Its solid base Special Defense means even one or two boosts push it into genuinely annoying territory for special attackers.
How to use it
You need a free turn — in doubles, that means either your partner buys you the turn, or the opponent's available options don't immediately threaten a KO. Even one use starts changing opponents' calculations. Two uses typically means standard sets can no longer OHKO. Get to three or more and they need dedicated removal like Clear Smog or Haze to get through.
Tips & strategy
The main risk in doubles is being double-targeted. Protect and Speed together are your tools here: use Speed to set up before the opponent acts, use Protect to absorb their response. The key constraint: all stat boosts disappear on switch-out. Natural Cure can clean status coming back in, but the Cosmic Power stacks are gone. This strategy rewards keeping Starmie on the field rather than cycling it.