Ability · Gen 6 · 1 Pokémon
Primordial Sea
On switch-in, heavy rain begins until this Ability is not active in battle.
On switch-in, the weather becomes Heavy Rain, which includes all the effects of Rain and prevents damaging Fire-type moves from executing. This weather remains in effect until this Ability is no longer active for any Pokemon, or the weather is changed by the Delta Stream or Desolate Land Abilities.
Primordial Sea was introduced in Generation 6. 1 Pokémon and forms can have it.
Pokémon with Primordial Sea
As a regular ability (1)
Kyogre-PrimalPrimordial Sea FAQ
What does Primordial Sea do?
On switch-in, the weather becomes Heavy Rain, which includes all the effects of Rain and prevents damaging Fire-type moves from executing. This weather remains in effect until this Ability is no longer active for any Pokemon, or the weather is changed by the Delta Stream or Desolate Land Abilities.
Which Pokémon have Primordial Sea?
1 Pokémon and forms can have Primordial Sea: Kyogre-Primal.
Effect text from Pokémon Showdown (MIT); which Pokémon have it from Showdown's Pokédex, cross-checked against PokéAPI. Unofficial fan site.