In battle
- Main article: Ignoring Abilities
When a Pokémon with Mold Breaker uses a move, the effects of all Pokémon's ignorable Abilities are ignored for the execution of that move. (Ignorable Abilities are most Abilities that could potentially negatively affect the success, damage, or effects of a move if possessed by the target of a move or its allies.) For example, a Pokémon with Mold Breaker that uses Earthquake can hit opponents that have Levitate.
In Generation IV, when a Pokémon with Mold Breaker is brought out, the message "<name> has Mold Breaker!" is displayed. From Generation V onward, when a Pokémon with Mold Breaker is brought out, the message "<name> breaks the mold!" is displayed.
Generation IV
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 by using a move that switches the target out (such as Roar or Dragon Tail), ignorable Abilities are ignored when applying entry hazards. For example, a Pokémon with Levitate switched in this way will be affected by Spikes and Toxic Spikes (unless it is also ungrounded for other reasons); if a Poison-type Pokémon with Levitate is switched in this way, it will remove Toxic Spikes from its side of the field (unless it is also ungrounded for other reasons).
If a Pokémon with Mold Breaker attacks, it does not gain Attack due to an ally's Flower Gift.
Generation VIII onward
Mold Breaker no longer ignores Dark Aura and Fairy Aura, though it will still ignore Aura Break.
Outside of battle
Mold Breaker has no effect outside of battle.