Sashi Kobayashi is the deuteragonist of the Disney XD animated series Penn Zero: Part-Time Hero. She is Penn Zero's friend at school and a part-time sidekick, the toughest and smartest of the team and, according to Rippen, "the competent one". Unlike Penn and Boone's parents, her parents are not part-time heroes.
Sashi is the most serious and intelligent of the three, and pays more attention than the others do. In every dimension she, Penn and Boone travel, it is her duty to describe their mission and what to expect in each world. She hates being mocked, yet some forms she takes are too humiliating for the others to take seriously (such as a clown or a cute fluffy stuffed animal). She is very aggressive, skilled at combat, and likely to threaten others no matter what side they are on. However, she does have enough faith in her friends, Penn especially, to be a trustworthy sidekick, and tries her best to be respectful to others as well. In "Flurgle Burgle", she is given credit for making a completed mission possible, and is congratulated with a cake that she is almost sickened by, but accepts as a reward.
- In "3 Big Problems", she is good at dodgeball at gym class.
- For Sashi's art project in "The Princess Most Fair", she brings a smashed television.
- Sashi's first name is an Indian name that means "moon," and her last name, Kobayashi, is a Japanese surname that means "small forest."
- As revealed in "Totally Into Your Body", Sashi has a crush on an older student name Teddy.