Tart comes to Earth with Pie to aid Kish in preparing the planet of the arrival of Deep Blue. Energetic and often childish, Tart taunts Kish for losing to the Mew Mews, saying he's weak. Like Pie and Kish, Tart can fly, teleport himself, and create chimera animas. He primarily fights with physical attacks and the chimera animals, but is also capable of manipulating plants and using them to bind people and to use an energy beam attack. In the anime, he is also shown fighting with a click-clack toy. Tart doesn't like Ichigo, and often argues with her until they descend to name calling. He doesn't understand why Kish would like an "old woman" like her. He particularly hates being called a "midget," which Ichigo uses to make him accidentally free a captive Pudding by taunting him into blindly attacking. He and Pie once captured Pudding and Tart was in charge of guarding her under the Tokyo Dome. During this encounter, Pudding bewilders him by refusing to cry, speaking to him in a friendly manner, giving him a piece of candy, and calling him her "bud."

After he is defeated by the Mew Mews, he calls Pudding "spooky," but then looks down at the candy she gave him and laughs. In the anime, rather than being saved by from the underground cavern by the Mew Mews, Pudding is saved by Tart after he realized she was starting to suffocate from a lack of oxygen. Towards the end of the anime, Tart catches Pudding when she falls from exhaustion and says he doesn't want to fight anymore. Pudding tells him that his being with her makes him stronger and puts her face close to his. At the end of the manga series, after Pie and Tart are defeated by the Mew Mews in the final battle, Tart tells Pudding that he never hated her, and Pudding cries over him. After Deep Blue is defeated and the aliens are preparing to return to their world, Pudding gets upset by Tart leaving and kisses him, giving him a candy drop at the same time. She also gives him other presents and tells him she doesn't want it to be goodbye. Tart blushes and says he may come back to get another candy drop from her.

In the anime series, Tart's voice actor is Asai Kiyomi. In the Mew Mew Power English adaptation, his name is changed to Tarb.