if riolu can have prankster and it evolves, does it stay prankster or does it just switch to another ability? i found 0 information about it, and I'm curious if it is possible
The Hidden Ability is implemented as a third slot, and a Pokémon with its Hidden Ability will retain its Hidden Ability slot upon evolution in the same way that its normal Abilities may change. For example, a Caterpie with its Hidden Ability of Run Away will have Shed Skin upon evolving once and Tinted Lens upon evolving into Butterfree.
source Same thing is true about prankster Riolu evolving into justified Lucario.
No. While Prankster Riolu is possible, Lucario has Justified as its Hidden Ability instead of Prankster. Hope this helps! Source: https://pokemondb.net/ability/prankster https://pokemondb.net/pokedex/lucario
