Octi is a purple stuffed octopus wearing a small black hat. Octi is Bubbles' most prized stuffed animal. As seen in The Powerpuff Girls Movie, it was given to Bubbles by Professor Utonium, Bubbles' creator.
- In the original series, Octi had two episodes revolved around him: Octi Evil and Octi-Gone. In the reboot, he had one episode focusing on him: Little Octi Lost.
- Despite being an Octopus, Octi only has four legs. However, this may have been due to eight legs being hard to animate.
- Octi wears a hat similar to the Mayor's hat.
- Octi is similar to Oswald the octopus from the Nick Jr. series.
- In seasons 5-6 he has six legs instead of four.
- In the 2016 series , Octi has no hat. However, his hat can be seen in the opening sequence.