As a wild Pokémon
Krookodile made his first appearance in A Sandile Gusher of Change! as a Sandile, where he was revealed to be the leader of a group of Sandile who lived near a local spa resort. He and the group caused trouble at the spa resort on Route 1 so that they could get the attention of the owners. He was actually trying to save the other Pokémon in the area because he knew that a geyser would soon erupt. With the help of Ash, Iris, and the son of the spa resort owner, Dan, Sandile was able to save the Pokémon. In the end, Sandile was shown to have gained respect for Ash, and as such, began to follow him.
Sandile appeared again in Here Comes the Trubbish Squad!, where he wanted to battle Pikachu. He randomly attacked with Stone Edge, despite there being small children close by. He was sent blasting off by a wild Trubbish's Sludge Bomb and Pikachu's Iron Tail.
Sandile reappeared in Dancing With the Ducklett Trio!, separating Ash from the group in order to battle Pikachu again. However, a wild Ducklett stole his sunglasses and stopped the battle. Sandile was deeply saddened without his sunglasses, losing his usual confidence and becoming quite cowardly. With Ash and Pikachu's help, he defeated the Ducklett and reclaimed his sunglasses. Later, after being healed at the Pokémon Center, Sandile finally got the battle he wanted with Pikachu. Sandile dominated the battle to start with and eventually evolved into Krokorok. Pikachu soon gained the upper hand however, and sent Krokorok blasting off when his Electro Ball attack collided with Krokorok's Stone Edge, causing the stones to hit Krokorok and send him flying.
After a long absence, Krokorok returned at the end of Explorers of the Hero's Ruin! with the same goal of defeating Pikachu in battle. In the following episode, he battled against Pikachu, and ended up causing the two of them to go flying. He was later found by Ash, and helped them locate Pikachu. It was revealed that Krokorok had followed them through various locations, including Nimbasa Town and Nimbasa City, in order to have a rematch with Pikachu. He also followed them through Chargestone Cave, where he was shown to be the cause of a pen being stuck in the Klinklang in Evolution Exchange Excitement!. Krokorok later allowed Ash to use him to help Mick learn to battle, and he eventually teamed up with Pikachu under Mick's command in a Double Battle against Sean's father's Seismitoad and Scolipede, where the duo eventually won. Krokorok then got the chance to battle Pikachu like he had wanted for so long, and after a hard-fought battle, Pikachu emerged victorious. Krokorok was depressed by the loss and begun to leave, when Ash invited him to join their team. Krokorok happily agreed, and was caught by Ash in a Poké Ball.
In An Amazing Aerial Battle!, Ash used Krokorok in his Gym battle against Skyla. He faced her Swoobat, who she had previously predicted would beat him. Krokorok struggled in the battle having all his moves evaded while narrowly escaping Swoobat's. Krokorok finally was able to land a single hit with Stone Edge before Swoobat countered it with a powerful Air Cutter, defeating him.
In Guarding the Guardian of the Mountain!, Ash chose Krokorok for some special training with Brycen and his Beartic. When the training began, Krokorok and Ash had problems on following Brycen and Beartic's techniques, especially when they had to jump down a waterfall and Krokorok refused to, due his fear of water. Later, Krokorok was used in a battle against Pokémon poacher Rizzo in an attempt to free the guardian, Volcarona, of the mountain they were training on. He battled a Jellicent and was hit by a super effective Hydro Pump after missing with Crunch. Regardless, Krokorok got back up and landed several hits on his opponent with Stone Edge before using Crunch again, though it was deflected. Krokorok attempted Crunch from a different angle, only to receive a painful hit from Jellicent's Hex attack. Persevering, Krokorok avoided his opponent's Confuse Ray with Dig and finally landed an effective hit with Crunch on the Ghost-type Pokémon. Krokorok tried another Crunch, only to be stopped by Hex again, though he dodged Confuse Ray with Dig and hit Jellicent with Crunch, as he did before. Rizzo then brought out a second, female, Jellicent which hit Krokorok with her Confuse Ray. Krokorok was then hit by a double Hydro Pump and sent into Rizzo's cage along with Volcarona. He and the Sun Pokémon were eventually rescued by Brycen and Beartic.
In Caution: Icy Battle Conditions!, Krokorok was pumped up for the upcoming Gym battle and accompanied Ash to the Gym outside of his Poké Ball. He started off battling Brycen's Vanillish, and began with a Crunch, but was halted by Vanillish's Astonish. After the collision of Stone Edge and Icicle Spear, Vanillish launched a Blizzard that froze Krokorok while he was attempting to dodge with Dig. After being knocked while frozen by Mirror Shot, Ash recalled Krokorok, though the Mirror Shot thawed him. He was later sent out to battle against Beartic. Krokorok's Stone Edge was deflected by Beartic's defensive Icicle Crash, causing the Stone Edge to hit Krokorok and then Krokorok's Crunch was countered by Ice Punch freezing his mouth. Krokorok narrowly escaped a super-effective Brine by using his tail to jump onto an ice pillar, climbing it, this enabled him to shake off the ice, then finally landing a direct hit with a super effective Stone Edge whilst mid-air. Krokorok was then able to land a direct hit with Dig; however, this allowed Beartic the chance to grab him by the tail and throw him across the battlefield into a large mound of ice. However he then broke free. Seeing the broken ice made Ash think of Stone Edge and gave him an idea. Ash then ordered a Stone Edge attack that was deflected again by Icicle Crash. However, Krokorok jumped up and grabbed two of the stones, charging down from the air with the Stone Edge in hand to meet Beartic's Aerial Ace. After the collision, Beartic was knocked out, leaving Krokorok the victor and winning Ash the Freeze Badge.
In Ash, Iris and Trip: Then There Were Three!, Ash used Krokorok during his battle against Iris's Dragonite in the semi-final round of the Pokémon World Tournament Junior Cup. Krokorok's attacks were initially dodged and he was hit by Flamethrower. Krokorok managed to dodge many of Dragonite's attacks with Dig, though he still took some hits, and clamped down on his opponent's tail with Crunch. He was thrown off, but still managed to hit Dragonite with Stone Edge before missing with Crunch and getting hit by Flamethrower. Krokorok tried another Crunch attack but was rapidly hit by two Flamethrower attacks and an Ice Beam. To everyone's surprise, Krokorok then evolved into Krookodile and hit his opponent with a newly learned Dragon Claw. Dragonite then began to thrash about, launching its attacks all over the place in temper, but Ash ordered Krookodile to attack anyway. Krookodile was finally able to win the match by easily dodging Dragonite's Dragon Rush with Dig and landing a direct hit with Stone Edge.
In Meloetta and the Undersea Temple!, Ash sent Krookodile out to battle Meloetta after Oshawott had refused to battle it, not wanting to hurt the Pokémon he loved. Meloetta started the battle with Hyper Voice, which was strong enough to push Krookodile back. The Intimidation Pokémon then attacked with Stone Edge, which was, however, blocked by Meloetta's Close Combat, much to Krookodile's astonishment and annoyance. Ash then told Krookodile to use Dragon Claw, but before the attack could hit, the battle was interrupted by Ridley's Golurk, as he thought they were trying to hurt Meloetta. The Melody Pokémon was, however, able to convince him that Ash and his friends were harmless.
In Strong Strategy Steals the Show!, Ash chose Krookodile as his first Pokémon in his Vertress Conference battle against Stephan and his Liepard. The battle started with a clash of Liepard's Shadow Claw and Krookodile's Dragon Claw, after which Liepard followed in suit with Shadow Ball, which was countered by Krookodile's Stone Edge. Liepard then tried to attack with Hyper Beam, which Krookodile avoided with Dig. To prevent Krookodile from attacking Liepard after resurfacing, Stephan had Liepard use Double Team. Thanks to this, Liepard was able to strike Krookodile with Shadow Claw and Shadow Ball in succession, before Krookodile finally managed to strike Liepard with a Stone Edge. However, Liepard quickly hid itself amongst its copies again with another Double Team, and successfully hit Krookodile with a Hyper Beam, despite of his attempt of a Dig dodge. Ash then told Krookodile to use Dragon Claw once again while Stephan had Liepard to use Shadow Claw again as well. As this sideswipe of moves didn't cause either of the weakened Pokémon to fall down, the same clash was then repeated, and this time, Liepard was defeated. When Stephan sent out Zebstrika, Ash recalled Krookodile. The Intimidation Pokémon was later sent out to battle with Stephan's final Pokémon: Sawk. After a fierce exchange of Dragon Claw and Close Combat, when Sawk prepared to strike back with Karate Chop, Ash took Stephan by surprise by telling his Pokémon to use a new move: Aerial Ace. The super effective move on the Fighting-type Pokémon did its work, and Sawk was defeated, winning the match for Ash and eliminating Stephan from the tournament.
In Team Plasma and the Awakening Ceremony!, Krookodile was sent out alongside the rest of Ash's team to help Ash and N dig up to the surface of the White Ruins after they had fallen into a pit. He used Dig to help Charizard and the others get through the earth that Oshawott had softened with Hydro Pump. While battling Team Plasma, Krookodile cleverly used Dig to fire tons of rubble towards the opposing Pokémon to weaken them. However, when Colress turned his mind control machine on them, Krookodile was quickly recalled to his Poké Ball along with Ash's other Pokémon. In What Lies Beyond Truth and Ideals!, Krookodile later helped trap Ghetsis, Colress, Aldith and Barret with Stone Edge so they wouldn't be able to escape and could be arrested by Looker.
Krookodile remained on Ash's team as he began his travels in the Decolore Islands, but was eventually sent to Professor Oak's Laboratory in Butterfree and Me so that Ash could receive Leavanny to assist with a Caterpie. He was reunited with Ash and the entire Unova team at the lab in The Dream Continues!. He joined the others in a group attack on Team Rocket with his Stone Edge to send them blasting off for the last time in the Best Wishes series. Krookodile later posed in a group photo with the rest of Ash's Pokémon. Then, he was left at the lab when Ash set off for the Kalos region.