The tadpoles first appear as black-skinned tadpoles with stubby tails and big black eyes inside small, green egg sacs. Among them, two of the tadpoles are conjoined twins, and Katrina appears to be the smallest with the biggest and most expressive eyes.
At the end of "Starsitting", the tadpoles each grow a pair of frog legs; Katrina's legs are the most muscular. By "Puddle Defender", the tadpoles have shed their protective egg sacs and (save for Katrina) grown arms. By "Is Another Mystery", Katrina has also grown arms.
In the season 1 finale "Storm the Castle", Ludo gives the tadpoles to Buff Frog as a bribe to get him to kick Toffee out of Castle Avarius. However, Buff Frog unexpectedly becomes fond and protective of the tadpoles and adopts them as his children.
In "Starsitting", Buff Frog asks Star Butterfly to babysit his tadpoles while he leaves on a job, and he asks that she be especially careful with the youngest, Katrina. As Star and Marco watch over the tadpoles, Star accidentally disrupts their nap and mistakenly feeds them cake, causing them to make a mess. With Marco's help, Star manages to keep the tadpoles under control before Buff Frog returns to pick them up. During the episode, the tadpoles grow their frog legs.
In "Puddle Defender", the majority of the tadpoles have matured enough to grow arms. Katrina has not yet grown arms, but she reveals to Star that she can talk, unlike her siblings, something that her father is unaware of.
In "Is Another Mystery", Katrina and the rest of the tadpoles leave Mewni with their father to escape the constant prejudice toward monsters.
- Theme Song (season 2)
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- It is currently unknown where Ludo got the tadpoles from before giving them to Buff Frog.
- In some shots in their appearances, there are thirteen tadpoles (counting two in the same egg), despite the fact that Buff Frog tells Boo Fly he has twelve.