The frog-generation ability represents their frog-catching obsession, while the "sacrifice a Frog for +1/+1 counters" tries to recreate their eat-to-grow-stronger philosophy
The same is true for our other legendary cards, including Gantu, who is not only known for being strong but also tends to underestimate creatures smaller than him
Other cards with the Boost keyword or put a card under abilities would be great
The decks other character, Cruella De Vil, Miserable as Usual, is a much cheaper card able to be played earlier on, and can force characters off the field when shes banished by returning a character to its players hand - playing into the decks more control-like tendencies
You'll see these adorable icons across several beloved cards from Magic: The Gathering FINAL FANTASY and its Commander decks, with dazzling treatments to match
Hes not the only Big Hero 6 character with two versions