Brock's Croagunk

Brock's Croagunk (Japanese: タケシのグレッグル Takeshi's Gureggru) was the first that   in the Sinnoh region, and his ninth overall.

Croagunk was first seen resting outside a supermarket in Gymbaliar!. When emerged from it, Croagunk followed him to where  was using a fake Gym to steal unsuspecting s' Pokémon. Their plan was going badly as it required Jessie to win, but her kept losing. As a result, she spotted Croagunk and decided to use it, subsequently winning many s with it. After and  entered the Gym, Croagunk lost against Ash's Aipom. Team Rocket resorted to grabbing Ash's Pikachu and running off, leaving Croagunk behind in the process. Brock was the first to notice Croagunk and felt a connection with him; Croagunk later willingly went into Brock's Poké Ball.

Croagunk was first used in a battle by Brock in Leave It To Brocko!, battling. The two had a brief clash of moves before Croagunk repeatedly used while Seviper used  on him, eventually ending in a draw.

Like Brock's Bonsly, Croagunk has attacked Brock in order to continue the 's running gag of keeping Brock away from the girls who are the objects of his affection, to the point that even Croagunk's presence can be sensed by Brock, which may make Brock suddenly halt his romantic advances. In All Dressed Up With Somewhere To Go!, Brock entered Croagunk in the Pokémon Dress-Up Contest, an event organized by the Pokémon Fan Club where Pokémon try to imitate other Pokémon. Throughout the competition, Croagunk replicated the behavior of a and his impression of the  was so convincing that the panel of judges—formed by Mr. Sukizo, Nurse Joy, and Officer Jenny—deemed him the winner. As a result, Brock was given the Pokémon Egg prize.

In Glory Blaze!, Croagunk was briefly seen battling a and a  alongside Holly's  in the second round of the Hearthome City Tag Battle Competition. Together they managed to defeat their opponents and advance their Trainers to the semifinal round. In Smells Like Team Spirit! he was used in the semi-finals, being paired off with Holly's and was up against Ash's Staravia and Paul's Torterra. Paul showed total disregard for Ash, ordering Torterra to blast Farfetch'd with Hyper Beam, not caring that Staravia was hit as well. With Farfetch'd out, Croagunk challenged Torterra and managed to damage it with a powerful Brick Break to the head. Before Croagunk could follow up, Torterra recharged and hit Croagunk with Leaf Storm, winning the round single-handedly.

In Enter Galactic!, Croagunk protects Brock from a launched by Saturn's Toxicroak. The two quickly gain a strong disliking of each other and begin fighting. The fight is ended prematurely when Saturn recalls so Team Galactic can escape.

In Cream of the Croagunk Crop!, Croagunk and Brock enter the Pastoria Croagunk Festival. Croagunk initially enters the stage and has his physical condition judged alongside the other Croagunk, with the judges becoming impressed with Brock's Croagunk. The next part has Croagunk go through a brick-breaking contest, with he does flawlessly, allowing him to challenge the former champion, Craig. The two take to the boxing ring and begin the match and Craig quickly lands a powerful and follows up with. Croagunk dodges and lands multiple attacks against Craig. The two seem evenly matched but are interrupted by Team Rocket. The two Croagunk, alongside the rest of the participants, attack the mecha, only to be trapped inside. However, Nurse Joy and her Croagunk, Chrissy, stop them with a. Chrissy's heroism led to the coronation of Nurse Joy and her Croagunk as champions of the festival, giving Brock's Croagunk an automatic disqualification.

In Losing Its Lustrous!, Brock begins flirting with a Nurse Joy, but after a few seconds feels that something is wrong and notices that Croagunk didn't stop him. He notices him instead staring out a window, causing Brock to worry over Croagunk's behavior. The reason is later revealed to be Croagunk sensing Saturn's Toxicroak with his Ability. When it ends up getting close to Brock's location Croagunk releases himself from his Poké Ball and runs off to find it and start a battle. Later on Croagunk is seen falling through the skylight and lands hard on the ground. Toxicroak follows and hits Croagunk dead-on with a Poison Jab, knocking him out while Brock watches helplessly on from the roof.

In Battling a Cute Drama!, Brock met a Trainer named Marilyn and quickly became irritated by Marilyn's superficial attitude towards Pokémon. He decided to teach her about the inner strength and beauty of Pokémon with a battle and used Croagunk as his second Pokémon. Croagunk gains the upper hand against her, but it is just an act as Marilyn wanted to see Chingling take the attacks to make it more dramatic. Marilyn orders Chingling to use along with  and Croagunk is almost knocked out by the super effective move. Brock, not willing to give up, encourages Croagunk to keep going, and not wanting to let Brock down he does so and uses Brick Break, defeating Chingling.

In A Faux Oak Finish!, Croagunk guided the group through a marsh on the outskirts of Twinleaf Town. Using his skills, Croagunk was able to find safe spots for the group to walk on. Later, he encountered a Politoed and battled it.

In The Needs of the Three!, Croagunk once again battled with Saturn's Toxicroak. He quickly gets distracted and is hit by, so Brock recalls him. Later on the group attack Team Galactic again, with Croagunk leaping off of to land a direct hit on the head with Brick Break to Toxicroak, knocking it out and giving Croagunk his first victory over it. He then assists in freeing the and fighting  and.

Croagunk reappeared in SS027, once again halting Brock's romantic advances on Nurse Joy. Witnessing the dynamic between Brock and Croagunk, commented on their unique and spicy relationship.

Personality and characteristics
Croagunk is very calm and collected and appears to be unaffected by some attacks (as seen when Seviper used Wrap on him). He has an excellent hearing ability as he could hear in the bush in Setting the World on its Buneary! and Team Rocket sneaking into Oreburgh Gym in O'er the Rampardos we Watched!, can sense things easily, and is depicted as being very intelligent. He is quite stealthy as he could leave a room without Brock even noticing that Croagunk left to find out what a noise was. Croagunk has been shown to have his own pace for things like eating, attacking, or following Brock. Similar to, he is also a bit of a loner, preferring to sit alone when eating or just resting. Although he is seen mostly angry or without any emotion, he was seen happy in Doc Brock!. Croagunk has been shown to be vain at times, once spending hours staring at his own reflection and having to be dragged away from it to help deal with Team Rocket.

He is a very powerful Pokémon, as demonstrated in his debut episode where he beat many Trainers while he was under Jessie's command. He has since become Brock's main battling Pokémon and has proved his power again and again, even stopping a attack in The Rise of Darkrai. He has developed a rivalry with one of the other strength-oriented Pokémon on the cast, Ash's Buizel. He also has an extreme rivalry with Saturn's Toxicroak, to the point of actually ignoring Brock's advances on women.

Croagunk often attacks Brock to keep him away from the girls who are the objects of his affection, to the point that even Croagunk's presence can be sensed by Brock, which may make Brock suddenly halt his romantic advances. When forcefully dragging Brock away from girls, he usually uses, which makes Brock suddenly collapse so Croagunk can easily drag Brock away. However, when Brock pledged to save Oralie's and Haley's  in Ya See We Want An Evolution!, Croagunk still jabbed Brock, which caused  to remark that Croagunk may have gone too far. Croagunk generally chuckles or laughs after attacking Brock, so it is possible that he actually enjoys it. However, Croagunk has also protected Brock from harm, such as falling off a bridge in Bibarel Gnaws Best! and from Saturn's Toxicroak's attack in Enter Galactic!. According to the Pokétch in Not on MY Watch Ya Don't!, Croagunk is very close to Brock. In fact, Croagunk is about as close to Brock as is to, despite at the time having only been with him for two episodes, as opposed to Pikachu, which has been with Ash since the very first episode.

In the movie adaptations
Brock's Croagunk appears in the following manga adaptations of Pokémon movies: and.

In the TCG
Brock's Croagunk is featured in the TCG as a TCG Pokémon M (Pokémon). The following is a list of cards named Croagunk .

Trivia

 * Croagunk was Brock's first Pokémon with both his gender and Ability confirmed.
 * Croagunk was featured in a promotional C-Gear in Japan to celebrate SS025, the anime special featuring . This skin was later distributed internationally to tie in with the distribution of a Croagunk that knew at an early level, as well as the release of a new  area,, where other Croagunk can be found.
 * For DP020, Professor Oak's Big Pokémon Encyclopedia is about Brock's Croagunk. He writes this about it: 「グレッグル　タケシにツッコミ　しびれびれ」 " is 's paralyzing comedic partner."