The Frog Prince is an unnamed character from the Smurfs episode "The Blue Plague".
He is a prince turned into a frog by an evil sorcerer. He has sought the help of somebody who can change him back to his original form within three days before the spell becomes irreversible. Fortunately, on the third day, he ran into Papa Smurf as he and his little Smurfs were out picking zingberries in the forest. Papa Smurf offered to help turn the frog prince back to normal by creating a poultice for him at Toadstool Ravine.
After several tries mixing up the poultice, with each try turning the prince from one animal form to another, Papa Smurf succeeded in restoring the prince's human form. The prince was so grateful for Papa Smurf's help that he offered his assistance in any way possible.
Brainy Smurf then alerted Papa Smurf to the presence of Gargamel, whom he had led into the Smurf Village, whom the prince responded to by grabbing the wizard by the collar and demanding him to hand over the Smurfs. Gargamel and Azrael then ran for it with the prince chasing after them until Papa Smurf grabbed the bag containing the Smurfs and switched its contents with Azrael, fooling the wizard into taking the bag with him in his escape.