Larvesta

Flame Body : Whenever a move makes contact with this Pokémon, the move's user has a 30% chance of being burned. 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 Magma Armor.

Swarm : When this Pokémon has 1/3 or less of its HP remaining, its Bug-type moves inflict 1.5× as much regular damage. Overworld: If the lead Pokémon has this ability, the wild encounter rate is increased.