Light Metal is an ability introduced in the fifth generation. It can only be obtained as a hidden ability until the eighth generation. All Pokémon possessing this ability are Steel type.
In battle, the user's weight is halved. This decreases the damage suffered by Low Kick and Grass Knot, increases the damage taken from Heavy Slam and Heat Crash, and decreases the base power of Heavy Slam and Heat Crash, as all these moves are calculated from the weight of the target and the user. Heavy Ball catch rate is not affected as it uses the species weight instead of the present weight.