If used on an Ultra Beast, the catch rate modifier is instead always set to 0.1×.
In all games except Pokémon Sun and Moon, if using the Heavy Ball would cause the wild Pokémon's catch rate to become negative, it is instead set to 1. In Pokémon Sun and Moon, it is instead set to 0, making it impossible to successfully catch such a Pokémon with a Heavy Ball in those games.
The Heavy Ball cannot be used in situations in which Poké Balls cannot be used, such as in wild battles with two or more opponents currently present or against a trial Pokémon. If used in a Trainer battle, the opposing Trainer will bat the ball away, wasting the item.
When a player uses a Heavy Ball, they are allowed to search their deck for a Pokémon with a Retreat Cost of 3 or more, reveal it, and put it into their hand. The user shuffles their deck afterward.
In Pokémon Sun and Moon only, a Heavy Ball will always fail to catch a Pokémon whose weight is less than 220.46 lbs (100.0 kg) and whose catch rate is less than or equal to 20. This is because the game will set the catch rate to 0 when the catch rate becomes negative due to the -20 modifier that is applied. The only catchable Pokémon that this affects are Beldum and the guardian deities.