Baby Smurf is one of several major Smurfs created by Studio Peyo that debuted in the cartoon series. He will soon make his comic debut in "Le Bebe Schtroumpf" ("The Baby Smurf" in English) in 1984, the first comic adaptation of a Smurf cartoon episode.
"Once in a Blue Moon" would be the first of several episodes designated as "premiere episodes" that would introduce new main characters to the Smurfs cast: Season 5's "The Smurflings", "Sassette", and "Puppy" would introduce a young Nat, Snappy, Slouchy, Sassette, and Puppy; Season 6's "Smurfquest" would introduce Grandpa Smurf; Season 7's "Smurf On The Wild Side" would introduce Wild Smurf (and his squirrel friend Chitter); and Season 8's "Lost Smurf" would introduce Nanny Smurf and Smoogle.
"All Creatures Great and Smurf" is the first episode that introduces the adult version of Natural Smurf, who in Season 5 becomes one of the Smurflings.
"All Creatures Great and Smurf" is a variation of one of Aesop's Fables, "The Farmer And The Viper", where a farmer who nurses a viper back to health becomes the victim of the viper's unchangeable nature, repaying evil for good. Adult Nat mistakes this situation for what TV Tropes calls an Androcles' Lion, in which an endangered animal that a person rescued returns the favor by rescuing its rescuer from danger.
In "All Creatures Great and Smurf" Papa Smurf's comment that "a leopard cannot change its spots" is a common phrase that comes from Jeremiah 13:23, which reads "Can an Ethiopian change his skin or a leopard its spots? Neither can you do good who are accustomed to doing evil."