d'artagnan
At the end of the first season, Will vomited a lot of bugs from other worlds, and D 'Artagnan should be one of them. Later, Dustin took it home as a pet. Dustin was named after D 'Artagnan, the protagonist in three musketeers, because he liked to eat the popular "three musketeers Chocolate Bar" at that time.
d'artagnan
D 'Artagnan is a larval form. When Dustin first discovered it, it was only the size of a finger, but this creature grew very fast and could adapt to the food in the human world (Dustin also fed it chocolate and all kinds of junk food).
d'artagnan
A few days later, D 'Artagnan grew from a yellow-green bug to a monster (magic dog) with a petal-shaped head and a hound-like body, and ate Dustin's pet cat.