Anne wants to keep a caterpillar as a pet, but she'll have to keep it a secret from Hop Pop.
Anne and Sprig are playing outside when they encounter giant wasps attacking a small creature trapped in the mud. After rescuing it, Anne discovers that the creature is a small caterpillar that resembles a cat, specifically Anne's cat Domino from back home. Anne immediately falls in love with the creature despite Sprig's reluctance to take it in, due to Hop Pop's strong stance against keeping pets, but Anne wins him over, dubbing the cat Domino II. Anne asks Hop Pop directly about taking a pet in, but he instead angrily goes off on how Sprig and Polly once had a pet tarantula named Charlie Bigbottom who would cause a mess. While still uncomfortable with Domino II, who has begun licking and "play biting" him, Sprig distracts Hop Pop with stories on Charlie Bigbottom while Anne sneaks the cat in.
The next morning, Sprig goes down to Anne's room to see that it is covered in cobwebs. He notices that Anne is covered in scratch marks from Domino II, but she insists that he is just getting used to the home environment. After spending a day hiding Domino II from Hop Pop and Polly, Domino II takes a nap, only for it to make itself a cocoon. Anne and Sprig start eating upstairs when Hop Pop catches them and demands to know what is happening. After hearing a noise, The three rush downstairs to find that Domino II is missing. Sprig mentions that it was black with white spots and Hop Pop reveals that they have taken in a Coastal Killapillar and that it has transformed in a deadly butterfly. Polly comes down to see what is happening causing Domino II to reacting ferociously.
Despite Anne's efforts in keeping Domino II at bay, the monster begins attacking the Plantars forcing Anne to lead it outside with one of its toys. After getting far away, Anne solemnly tosses its toy into the wild as Domino II leaves for good. Upon coming back, Anne apologizes and Hop Pop breaks down in tears, admitting that he misses Charlie Bigbottom. The next day Anne is cleaning up with Sprig telling her that it is not difficult to take in a wild beast and keep it as a pet (referring to her) and offers a stuffed doll version of Domino II to her which she lovingly hugs.
- Brenda Song as Anne Boonchuy
- Justin Felbinger as Sprig Plantar
- Amanda Leighton as Polly Plantar
- Bill Farmer as Hop Pop Plantar
- The "cat-a-pillar" was inspired by creator Matt Braly's cat Domino, who he adopted in 2016.
- Domino II's hatched cocoon resembles the open eggs from the Alien franchise.