Magma Armor

Full effect

This Pokémon cannot be frozen. If a Pokémon is frozen and acquires this ability, it will immediately thaw out; this includes when regaining a lost ability upon leaving battle. Overworld: If any Pokémon in the party has this ability, each egg in the party has its hatch counter decreased by 2 (rather than 1) each step cycle, making eggs hatch roughly twice as quickly. This effect does not stack if multiple Pokémon have this ability or Flame Body.

In game description

The Pokémon’s hot magma coating prevents it from being frozen.

Using Magma Armor in Cobblemon

Abilities are passive and always active, so Magma Armor 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.