The Heavy Ball (Japanese: ヘビーボールHeavy Ball), one of the many Poké Balls featured in the Gold and Silver games can catch large and heavy Pokémon such as Snorlax better then a Poké Ball. It has a dark blue top with lighter blue circles on either side at an angle from the central button, the topmost of which is the largest and the lower-most of which are tiny and almost the same shade of blue as the majority of the top.
Catch Rate[]
Unlike most Poké Balls, the Heavy Ball's catch rate is an absolute value rather than a multiplier, adding (or, for lighter-weight Pokémon, subtracting) an amount to the calculation based on the target Pokémon's weight. This can result in heavier Pokémon being substantially easier to catch than with any other variety of Poké Ball, excluding Master Balls.
-20 pts wild Pokémon weighing less than 451.5 lbs
+20 pts wild Pokémon weighing between 451.5 lbs and 677.3 lbs
+30 pts wild Pokémon weighing between 677.3 lbs and 903.0 lbs
0 (see Kurt)