Takeshi's Croagunk, a Poison- and Fighting-type Pokémon captured during his Sinnoh journey, first appeared at a mysterious gym run by Princess Powerzone, later exposed as a Team Rocket plot. It became a constant team member. Croagunk possesses a mischievous nature, frequently interrupting Takeshi's flirtatious advances towards women like Nurse Joy or Officer Jenny. It typically employs Poison Jab or physically drags Takeshi away by his collar during these interventions. Despite this behavior, Croagunk shows loyalty and combat effectiveness, participating in gym battles such as Takeshi's match against Kiawe in Alola where it supported Mega Steelix. Following Takeshi's decision to become a Pokémon Doctor, Croagunk accompanied him back to Sinnoh and assisted in medical duties at a Pokémon Center alongside Blissey. The Pokémon reappeared in Alola, continuing its characteristic interventions at the Pokémon Center there, and traveled with Takeshi to Akala Island. Later, during the World Coronation Series finals, Croagunk observed Satoshi's battle against Leon alongside Blissey. It remained part of Takeshi's active team during his continued travels, helping to save him from a troublesome Hatterene alongside other companions.