Citron's Horubee once lived in an abandoned Lumiose City subway car with a group of fellow Pokémon. This group endured persistent threats from a territorial Diggersby trying to claim their home. Citron and his younger sister discovered Horubee during this conflict, offering strategic battle advice that empowered it to defeat Diggersby and secure its dwelling. When external danger later forced the subway car's relocation, Citron, his sister, Horubee, and the entire Pokémon group—including the now-allied Diggersby—worked together to move the structure to safety. After this event, Citron and Horubee parted ways, though Horubee's companions urged it to follow Citron as its chosen trainer. Taking their advice, Horubee joined Citron.

In its first official battle as Citron's Pokémon, Horubee faced Satoshi's Pikachu; the match was interrupted before a conclusion. Later, during a gym battle between Citron and Satoshi, Horubee battled Pikachu again but lost to an Iron Tail counterattack after trapping Pikachu's tail with its ears. Horubee eventually evolved into Diggersby before Satoshi returned to Lumiose City for specialized training. Its documented battle techniques involve using its ears like hands for Double Slap, tunneling underground with Dig, firing mud projectiles via Mud Shot, creating illusory duplicates with Double Team, and executing the recoil-based Wild Charge—often combined with Dig to mitigate vulnerability.