Here comes a Prince, turned into a frog by a disgruntled Wizard. The frog wanders in a nearby swamp until he meets a Princess, who kisses him and turns him back into a Prince, so they can have kids and be happy ever after. But there are other variations to that story :
The Prince retains some of his amphibian nature and the Princess ends up giving birth to dozens of tadpoles. Prince and Princess turn the castle into a terrarium and start breeding flies to feed their offspring.
The ?ever after? bit is so cliché. In real life, the Prince dies of prostate cancer; the Princess catches Alzheimer's disease, which explains why she kissed a frog in the first place.
The Prince is be perfectly happy with being a frog. Not only flies taste good, but the position has little of the inconveniences of ruling power e. g. treaties, wars, riots, treacheries, plots, murders. As a bonus, female frogs are much more easygoing than Princesses, and much sexier, so the Prince has no real need for a Princess.
When in his frog-state, the Prince sired a good many frogs. His rejected, dispossessed bastard frog sons foment a revolution with the help of peasantry allied with the rising bourgeoisie, depose the Prince and put one of them in his stead. Which frog could be a problem though, the damn critters all look alike.
The Princess is short sighted, steps on the frog by mistake and crushes it, a funny moment captured on video and that ends up on YouTube.
The Princess is French and eats the frog.
The Princess refuses to kiss the frog, because it's not in her contract to kiss slimy animals. Furry ones with Bambi eyes are OK, though rarely found in ponds.
The Princess? kiss fails and does not turn the frog back into a Prince, leaving both of them with a slimy aftertaste and sorely disappointed with life, fate and the ending of fairy tales.
The Princess's kiss turns the frog into a two-headed aardvark. Reinstating the aardvark as head of state raises hairy constitutional issues.
The frog is turned back into another Princess (it's hard to tell males from females in some species). Some ponytailed constitutional issues etc.
Kissing the frog turns the Princess into a frog herself. Tadpoles follow.
Kissing the frog turns it into a Very Big Frog, ox-sized. The search for a Very Big Princess starts.
Back into his human form, the Prince sternly refuses to sleep with a Princess with abominable kinky sexual preferences such as kissing frogs she just met. No way that slut will ever bear his children.
The Princess is very upset at the Prince's rather unappealing, coarse human form, he who was such a lovely frog. No way she'll ever carry children from that brute.
Right after he's turned into a frog, the Princess has a state-coach accident and ends up in a wheelchair. When she gets to the swamp for a frog-kissing session, her wheelchair bogs down and she can't go further. Instead, she takes up kissing rattlesnakes, at least they live on dry ground.
As a frog, the Prince turns out to be of an endangered species so that kissing them is strictly forbidden. Nature wardens and barbed wire prevent any frog-kissing, frog-fondling and frog-hugging, but frog-watching is OK.
When the Princess arrives to the swamp, she finds hordes of Princesses already canvassing the ground, some using hi-tech frog-detection devices, some just making a lot of noise. Others are not sure about what a ?frog? is and kiss everything that moves, which will leave deep psychological scars to many unfortunate swamp creatures. After a couple of days, the swamp looks like the Azincourt battleground. Little white bellies of poor animals float listlessly around.
The Princess kisses the frog, but has an allergy to frog slime that turns her head into a balloon with Wiener-sized puffy lips. She's straight-to-convent after that.
Frog slime is hallucinogenic. Hilarity ensues (at first).
The Prince has