Desolate Land

Full effect

When this Pokémon enters battle or gains this ability, the weather becomes extremely harsh sunlight. Extremely harsh sunlight has all the properties of Sunny Day and also causes damaging Water moves to fail. Extremely harsh sunlight ends when this Pokémon leaves battle or loses this ability, or when this ability is nullified. The weather cannot otherwise be changed except by the effects of Delta Stream and Primordial Sea. Air Lock and Cloud Nine will prevent the effects of extremely harsh sunlight, including allowing Water moves to work, but will not allow the weather to be changed.

In game description

The Pokémon changes the weather to nullify Water-type attacks.

Using Desolate Land in Cobblemon

Abilities are passive and always active, so Desolate Land costs you nothing to run. If it is marked hidden on a species above, expect it to be harder to obtain: servers differ in whether hidden abilities come from breeding, an Ability Patch, or events.

See the Pokedex for which abilities each species can have, and IVs, EVs and breeding for how to actually pass one down.