Goodbye Yellow (さよならイエロー Sayonara Ierō Goodbye Yellow) 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