|This article is about a/an episode in Choudenshi Bioman.|
Goodbye Yellow (さよならイエロー Sayonara Ierō) is the tenth episode of Choudenshi Bioman.
This episode is a peculiar episode in the history of Super Sentai in being the final episode of a character without the actual actor appearing in the episode. Due to matters during Bioman's production leading to the possible firing of actress Yuki Yajima, who portrayed Mika Koizumi (Yellow4), this episode concludes her story with her death. Yajima herself does not appear outside archival footage at the end, with her entire performance done in her Yellow4 costume by her suit actor and with all of her lines spoken by voice actress Mayumi Tanaka. In regards to the story leading to this, this is the first appearance of the element of "Anti-Bio Particles", which are key regarding the destruction of planet Bio and will be further explored much later in the story.
In the Philippine Dub, the title of the episode changed to "Yellow Four's Gift of Life".
Doctor Man develops a gun devised of Anti-Bio Particles to destroy the Bio Particles within the Bioman, forcing Mika to make a move that may ultimately prove to be fatal!
The Neo Empire Gear are ready with their best weapon yet; a gun that fires beams that completely negate the bio-particles in Bio Robo and the Biomen. The Biomen learn this the hard way when they fight a giant mecha and Mason zaps Bio Robo, leaving it defenseless. The Biomen are soon forced out and Mason tries to zap Red1, but Mika (Yellow4) takes the hit, which severely injures her. Peebo manages to rescue the Biomen, but Mika is M.I.A. Mika realizes the gun already used up so much power, it'll soon be useless--however, her injuries are proving to be mortal even she tries to defend Hikaru from getting shot. As Hikaru tries to help Mika they were soon cornered by Mason and his squad but only interuppted by Shiro and the group which they rammed the mechaclones to rescue both.
As Shiro and the group reveals about Mason's anti-Bio weapon from Mika with the use of her Bio Hologram, Mason arrives with the squad to confront them and threatens the Biomen with the same fate as Mika. Knowing she's dying anyway, Mika pushes the other Biomen out of the way and absorbs the rest of the gun's power. The Biomen wanted to help her as Mika tells them that she will take the hit from the anti-Bio weapon's shots and acts as a martyr to make Mason to empty his power as her plan. Her plan works however, Psygorn knocks the Biomen with his Fire Blast to make an open fire at the dying Mika and is eventually killed from its second hit in explosion. The Biomen avenge Mika by taking out the mechaclones and Psygorn as well as its mechagigan Chameleon Canth. After destroying the mecha, Shiro and the group mourns in Mika's funeral as the Bio Robo's eyes glowed to reactivate Mika's bio particles to trigger the Bio Hologram to flash a footage of Mika which they saddened over her loss. Shiro later carries Mika's corpse in her Yellow4 form along with his group and Peebo, walking away.
- Shirou Gou (郷 史朗 Gō Shirō): Ryōsuke Sakamoto (阪本 良介 Sakamoto Ryōsuke)
- Shingo Takasugi (高杉 真吾 Takasugi Shingo): Naoto Ōta (太田 直人 Ōta Naoto)
- Ryuuta Nanbara (南原 竜太 Nanbara Ryūta): Akito Ōsuga (大須賀 昭人 Ōsuga Akito)
- Mika Koizumi (小泉 ミカ Koizumi Mika, Voice): Mayumi Tanaka (田中 真弓 Tanaka Mayumi)
- Hikaru Katsuragi (桂木 ひかる Katsuragi Hikaru): Michiko Makino (牧野 美千子 Makino Michiko)
- Peebo (ピーボ Pībo, Voice): Yoshiko Ōta (太田 淑子 Ōta Yoshiko)
- Doctor Man (ドクターマン Dokutā Man): Munemaru Kōda (幸田 宗丸 Kōda Munemaru)
- Mason (メイスン Meisun): Hirohisa Nakata (中田 博久 Nakata Hirohisa)
- Farrah (ファラ Fara): Yōko Asuka (飛鳥 裕子 Asuka Yōko)
- Monster (モンスター Monsutā): Strong Kongō (ストロング金剛 Sutorongu Kongō)
- Psygorn (サイゴーン Saigōn, Voice): Keisuke Yamashita (山下 啓介 Yamashita Keisuke)
- Last appearance of Mika Koizumi as a main character.
- Peebo cries over Mika's death.
- Yellow4 is never shown untransformed in this episode due to Yuki Yajima quitting the show (the reasons why are unknown and there has been different theories on this, one theory says that she left the show due to pay issues with Japan Action Club, while another version is that, according to Ryosuke Sakamoto who plays Shirou Gou/Red1, during an interview in a conference in Japan Expo 2003 in France, Mika's death in the tenth episode was already planned since the start of the series to show that arrogance could lead to defeat). Also, her voice was dubbed over by an uncredited Mayumi Tanaka as Yuki Yajima had only completed ADR for the first nine episodes.
- Near the end of the episode, Bio Robo's Eyes Glowed trigerring the Bio Hologram to flash a footage of Mika. That footage is actually Mika's Shot in the Closing sequence.
- Shiro's black short sleeve undershirt from his primary outfit is changed to white.
- Both Ryuta and Hikaru wear their second outfits in this episode.
- In the Philippine Dub, this is also the final appearance of Mika Koizumi's original voice actress, Geraldine Oca.
Choudenshi Bioman Volume 1 features episodes 1-11.