Harley and Cacturne met up with May, who scanned Cacturne with her Pokédex. She noted how scary it looked, despite just standing around. Harley and Cacturne participated in the Izabe Island Pokémon Contest, where Cacturne used Bullet Seed. This formed a mark of a skull and crossbones, which impressed the judges to let Harley into the next round. Cacturne fought against an Azurill, who used Bubblebeam, followed by Slam. However, the bubbles got pierced by Cactrune's Poison Sting and Azurill was defeated by its Bullet Seed. In the final round, Cacturne faced May's Bulbasaur. Cacturne started with Poison Sting, but was negated by Bulbasaur's Vine Whip. Bulbasaur also launched Razor Leaf, but was negated with Cacturne's Bullet Seed. It was soon hit by Bulbasaur's Vine Whip and Tackle. After May got embarrassed by the story Max told to Harley, who recorded the conversation and played it, Cacturne kicked Bulbasaur away. Bulbasaur tried to attack with Vine Whip, but got hit by its Poison Sting attack and missed using Razor Leaf. Bulbasaur tried to use Petal Dance as well, but also missed. May, however, managed to cool down and had Bulbasaur stop Cacturne's Feint Attack with Vine Whip. With Petal Dance and Razor Leaf, Cacturne was severely wounded and defeated, making Harley lose the Contest.
Before arriving to Slateport City for May's Grand Festival, she and Ash remembered their past adventures so far. May recalled meeting Harley and his Cacturne, the former being really annoyed by her "lack of knowledge and odd behavior". In the final round of the Contest, Bulbasaur launched Razor Leaf, but missed and got hit by Cacturne's Poison Sting. Cacturne dodged Bulbasaur's Vine Whip and Petal Dance, then proceeded to finish Bulbasaur with Faint Attack. However, Bulbasaur binded Cacturne with Vine Whip and tossed it in midair, making it an easy target for Bulbasaur's Razor Leaf and Petal Dance attacks. Cacturne was defeated, which made May earn her fourth ribbon.
Harley also used Cacturne in the Appeal Stage of the Saffron City Contest in A Hurdle for Squirtle. Harley lent Cacturne to Jessie to use in the appeal round of the Mulberry City contest during New Plot, Odd Lot. After Harley sent it out, it automatically fell in love with Jessie. Harley explained this happened because he (Harley) and Jessie were soul-mates.
Harley used Cacturne in the Kanto Grand Festival in a battle against May where it battled along with Harley's Wigglytuff. It took on her Munchlax and Eevee but was quickly defeated with a combination of Focus Punch and Shadow Ball, respectively.The last time Cacturne was seen was during The Unbeatable Lightness of Seeing where it was used to expose Team Rocket and send them blasting off after May and Drew's battle.
|Bullet Seed +||A Cacturne for the Worse|
|Poison Sting +||A Cacturne for the Worse|
|Feint Attack||A Cacturne for the Worse|
|Pin Missile||Rhapsody in Drew|
|Cotton Spore||A Hurdle for Squirtle|
|Needle Arm +||A Hurdle for Squirtle|
|Cut||New Plot, Odd Lot!|
|+ indicates this Pokémon used this move recently.*|
- indicates this Pokémon normally can't use this move.