what does purifying a pokemon do

Purifying a Pokemon is a process in Pokemon Go where a Shadow Pokemon is turned back into a regular Pokemon. Purifying a Shadow Pokemon requires a combination of Stardust and Candy, and it will improve the Pokemons appraisal and reduce the amount of Stardust and Candy required for them to power up, evolve, or learn a new attack. When a Shadow Pokemon is purified, it will forget Frustration and learn Return, a Charged Attack thats exclusive to Purified Pokemon. Purified Pokemon will have better appraisal and receive 2 points towards all their IVs, which can potentially bring a 2-star Shadow Pokemon to a higher ranking. Purified Pokemon also cost less candy to evolve and less dust to power up, and they know Return, a normal-type attack. However, purified Pokemon lose the 20% damage bonus made available to Shadows, which can be less painful for certain Pokemon, but others do benefit highly from remaining as a Shadow Pokemon. The downsides to purification are that purified Pokemon lose the 20% damage bonus made available to Shadows, and the 2 IV increase is often dwarfed by the Shadow damage boost. The cost to purify a Pokemon can vary depending on the Pokemons buddy candy walking distance, and Stardust costs can range anywhere from 1,000 to 20,000.