Mold Breaker ignores the effects of Abilities that could potentially affect the damage or effects of a move that its user executes. For example, a Pokémon with Mold Breaker can hit opponents that possess Levitate by using Earthquake. Mold Breaker applies regardless of target Pokémon, but only to moves executed by its user (so if two Pokémon in a Double Battle both know Earthquake, only the Pokémon with Mold Breaker can hit a Pokémon with Levitate).
Unlike Gastro Acid, which completely negates a target's Ability, the opponents' Abilities otherwise remain in effect:
Abilities that prevent status conditions (such as Immunity and Oblivious) will not protect the Pokémon from receiving the status condition; however, many of these Abilities also have effects to cure the Pokémon of the status condition if afflicted, which are not negated by Mold Breaker.
Abilities that draw attacks to the user, such as Lightning Rod and Storm Drain, will still divert attacks regardless of Mold Breaker, but will not nullify the damage or boost the Pokémon's stats.
If a Pokémon with Own Tempo consumes a held Berry that may cause confusion in response to the move of a Pokémon with Mold Breaker, it will become confused if it dislikes the flavor (although Own Tempo will then activate and cure it of confusion).
Mold Breaker can ignore the Abilities of Pokémon other than the target; for example, if a Pokémon with Mold Breaker uses Thunder Wave on a Grass-type Pokémon whose ally has Flower Veil, the target will still be paralyzed.
In Generation IV, when a Pokémon with Mold Breaker is brought out, the message "<name> has Mold Breaker!" is displayed. In Generation V onward, when a Pokémon with Mold Breaker is brought out, the message "<name> breaks the mold!" is displayed.
Flower Gift will increase the Attack of allies with Mold Breaker, even when they are attacking the ally with Flower Gift.
Generation V onward
If a Pokémon with Mold Breaker forces a Pokémon to switch in with a move like Roar or Dragon Tail, Abilities that affect entry hazards will be ignored if possible; if forced to switch in this way:
Abilities that draw attacks to the user, such as Lightning Rod and Storm Drain, no longer divert attacks from a Pokémon with Mold Breaker.
When a Pokémon with Mold Breaker uses a move, even the effects of allies' Abilities (notably Flower Gift, Sweet Veil, Aroma Veil and Flower Veil) are ignored for the duration of that move. As such, if the move of a Pokémon with Mold Breaker triggers an Ability (such as Gooey or Cursed Body) or item (such as Destiny Knot), the Pokémon with Mold Breaker will not be protected by its allies' Abilities; likewise, if a Destiny Knot held by a Pokémon with Mold Breaker is activated during the use of its own move (such as in response to the target's Cute Charm), that target will not be protected by its allies' Aroma Veil. This also means that a Pokémon with Mold Breaker will not gain Attack due to an ally's Flower Gift.
Mold Breaker ignores the following Abilities, even in situations where the Ability could increase the power of a move (such as using Low Kick on a Pokémon with Heavy Metal or using a Fire-type move on a Pokémon with Dry Skin):
Damage dealt by the Pokémon's moves or items is not influenced by the target's Ability.* The Pokémon's moves are not influenced by the target's Ability! For example, it could make a Pokémon with Sturdy faint in one hit!*