>>16522284Every Pokemon species have two ability 'slots.' For mons with a single ability (ex. most Levitators), they simply have the same ability in both slots.
Each individual mon is classified as having either ability 1 or ability 2 for its ability.
All Clefable with Ability 1 will have Cute Charm. All Clefable with Ability 2 will have Magic Guard.
All Gengar with Ability 1 will have Levitate. All Gengar with Ability 2 will have Levitate.
The Ability Capsule will switch the value for that mon (whether they're an ability 1 or ability 2 mon).
Hidden abilities don't actually use or affect the ability slot, and are instead an extra trash byte that modifies whether the mon is a HA mon, which overrides the effective ability in place (all HA mons still are either ability 1 and ability 2).
As such, the Ability Capsule will have no effect on HA mons, and cannot change a non-HA mon into a HA mon.