Omny first appeared as an Omanyte inAs Gastly as Before, being sent out byMisty to try and pull downSuper NerdMiles from a sinister black fog. The dark fog reveals itself to be aGastly and shakes him off. After the Gastly is defeated byBlue, Mistygives Omanyte toYellow so she can better protect herself.
InEradicate Raticate!, Omny is sent out alongside his teammates to battle againstLance and hisDragonite. Omny attacks with a powerfulWater Gun, butDragonite simply shrugs it off and throws Omny away. He islater used in a team attack to try and stop Lance from shooting bubbles. Yellow hadKitty cover the volcano crater inString Shot to form a net that is doused by Omny's water, linked toRatty's sensitive whiskers. Upon Lance triggering the net, Ratty signals toPika to send electricity down the net, forcing Lance's bubble into view. Yellow then ordersDody to break the bubble withDrill Peck, but the attack proves too weak.
In the final battle against Lance inThe Might of... Metapod?!, after Yellow had lost thePokédex, Omnyevolves into an Omastar to gain more power. He then assisted in defeating Lance's team, attacking his Dragonite with an Ice Beam.
InA Well-Journeyed Jumpluff, Omny battledOrm and hisJumpluff. Due to the spores that Jumpluff released, it made it near impossible to release a Pokémon without getting astatus condition. Using her telepathic abilities Yellow moved Omny'sPoké Ball outside the spores' range. Once past, Yellow released Omny and had him freeze Jumpluff withBlizzard. The attack also froze the spores as well, causing them all to fall to the ground.
InPhew for Mew, Omny and Yellow found themselves petrified bySird, along with the four otherPokédex holders and their Pokémon.
InThe Final Battle VII, Yellow checked on Omny and the rest of her team to ensure they all survived the petrification caused byMewtwo andDarkrai.
Personality and characteristics
WhenYellow first got Omny, he was aggressive towards her,ignoring her commands and attacking her. This was due to the fact that he originally belonged to a powerfulGym Leader and Yellow had yet to prove herself to him. Over time, however, the two managed to develop a loving relationship, and now, Omny follows hisTrainer's commands without hesitation. He is one of Yellow's most powerful Pokémon and is her go-to pick for battling.
