Defeating a Team GO Rocket Grunt in a Trainer Battle rewards the player with 500. The Grunt will abandon the PokéStop (if not flee via hot air balloon), and leave one of the Shadow Pokémon used in battle, which can then be captured during the bonus challenge. Since November 5, 2019, starting in selected locations, a defeated Team GO Rocket Grunt will also leave behind a Mysterious Component needed to assemble a Rocket Radar.
When using a Super Rocket Radar, Decoy Grunts may be found disguised as Giovanni. Upon interacting with the PokéStop, they will reveal themselves to be Grunts and challenge the player to battle.
A Grunt's prebattle quote hinting at specializing in Fire-type Pokémon
The possible Shadow Pokémon used by each Team GO Rocket Grunt are based on the Grunt's gender and type specialty, which is hinted at by the quote on the prebattle screen. Team GO Rocket Grunts will always send out their Pokémon in the same order, with each of their three Pokémon independently and randomly selected from separate pools. The odds of each Grunt appearing and which Pokémon they use are not uniformly distributed. Team GO Rocket Grunts will also never use Protect Shields.
After a Grunt is defeated, they will abandon one of their Shadow Pokémon used in battle, which can then be captured during the bonus challenge. Although Grunts usually abandon the first Pokémon used, some have a small chance of abandoning the second instead. For Grunts that may abandon either the first or second Shadow Pokémon, the bonus challenge encounter is random for every player; for instance, if two players defeat a Team GO Rocket Grunt at the same PokéStop invasion, whose team consisted of Houndour, Houndoom, and Arcanine, one player may encounter Houndour while the other encounters Houndoom.
The following lists the possible Pokémon that may be used by each Team GO Rocket Grunt since April 3, 2022. Green-colored cells denote the pools of Pokémon that may be encountered during the bonus challenge.