I had this idea, which, I am going ahead with, via diorama (I make them using neca toys, predominantly).
My take on the TMNT franchise.
It's 1982 and an elderly asian immigrant is living in a camper van, that is parked up in an abandoned, unused storm drain in the new york region. His name, Hamato Yoshi.
Hamato fled Japan to start a new life in America, with no documents and little English, it was hard, but he perservered and was able to set up a modest home in his camper, working for little money and being paid in food - he makes fantastic trinkets, boxes and art from drift wood. The community did their best to accommodate him, but as winter got harsher, recessions, he slipped into the background.
Naturally, he's slightly more disheveled than this picture shows, but he's proud, clean as can be.
Kids would often see him walking in and out of the storm drains, looking for food and heading off too sell his art - they would nick name him the 'rat man' as his appearance from afar, did resemble a sewer rat.
One day, as fate would have it, he stumbled across 4 turtles, at the base of a drain, coated in a strange substance - Hamato collected them and put them in a large fruit jar, looking to sell them the next day at the market.
That night, as Hamato slept in his wagon, he heard a glass crack - to his amazement the turtles had doubled in size and broke out the jar.
Freaks of nature, gift from god or a sign of the times, Hamato kept them, studied them and monitored their progress in a diary. In the space of a week they were 3 ft tall and were anthropomorphic turtles, displaying interest in their surroundings and Hamato as a 'parent' figure.
Stocked up for the winter, Hamato was not seen again until the spring, along with urban legends and sightings of 4 child like creatures roaming the sewers.
A happy, unorthodox family, Hamato marvelled as he soon had 4 teenage like turtles - he named them Leonardo, Donatello, Raphael and Michaelangelo. To entertain them, he told them stories of his past his culture and of the world above, he taught them math, art and literature - to keep them healthy, focused, he taught them martial arts.
Hamato had already previously boarded off areas of the storm drains to keep himself safe, now they were child proof and safe in his underground world. They spent their days playing board games, reading, watching tapes on an old TV that mesmerized the turtles. It wasn't long before they were role playing the A team, playing ninja's around the sewers and listening to music on a radio. Their traits were undeniable and unique.
Leonardo and Michaelangelo gave themselves the name 'Teenage mutant ninja Turtles' as the 4 would play dress up in bandana's and reenacted Hamato's stories, against the evil Oroku Saki that they nicknamed 'Shredder'.
Donatelo would create cool gadgets - walkie talkies, sewer skate boards and they had many make believe adventures down there. Raphael would draw pictures, and created a mock up poster of their adventures and wrote them down as stories - he was submerged in that fantasy, drawing him into the world above.
They had a pet gecko, called Mondo and they had a thing for pizza.
No one disturbed them, no one knew they were there, sure, on a quiet night, or whilst waiting for the subway, a teenage laugh could be heard, footsteps and swooshing beneath the drains, but it was either punk kids or their imagination, until April O Niel, looking for her first scoop for the local station, ventured down to see if the urban legend was true.
.....
Basically, they look similar to the 1990 movie, but more child like in bodily appearance. They live under the city, in a storm drain with a VW camper van as the base.
They created this fantasy world where they role played as the TMNT to pass their time.
They get discovered by April, that draws them out of the shadows where they then find themselves in a situation where it's not a game... time to step up and be the 'teenage mutant ninja turtles'.
The sequels then delve into the mutagen and the foot.
This movie has a hint of Gremlins, Goonies and Big with a heavy retro, 80's backdrop.