Ladon

Ladon is the youngest of Echidna's children and the last one she bore before Typhon was imprisoned. Out of all her children Ladon is the only one who bares a physical resemblance to both his parents. He appears in Hercules:The Animated Series

Ladon don't appears in Once Upon a Time. He was represented by one of Hercules' twelve medals when telling his heroic past to an teenage Snow White and was depicted like his mythic description, a dragon/snake with one head (or 100 in others versions), recruted by Hera for to control the Hesperides Garden and the Golden Apples Tree.