(Note: this is modeled after my own particular headcanon for Rise of the TMNT. It's a bit darker and grimmer than the official show.)
The frozen rain roared through the underground tunnels, rushing past stone and cement, the run-off of dozens of streets pouring down gutters and carrying detritus of leaves and litter, chunks of ice, cascading through grates and out of pipes that emptied into corridors that ran into darkness.
The rain masked the scrape of teeth on bone.
Blood, steaming hot in the winter air.
Only half the usual amount on the dinner table—and Donatello strategically placed the unshelled walnuts in front of Raphael to slow him down. While Raphael cracked each between his fingers, eating them one half at a time, Donatello scooped up the salad and rice. Leonardo took what was left of the rice and moved it to Michelangelo, who'd finished the last of the beans. And that left—
Raphael had finished the nuts and was eating the half of the chicken.
There were chickpeas from a can they'd found in the back. Michelangelo was looking for something else, still hungry. Leonardo pushed the chickpeas to him. And that left—
Raphael finished off the last of the rolls.
And that left Leonardo.
Winter made for barren choices for food—fruit and vegetables were out of season, pigeons weren't laying eggs. The bodegas gathered people escaping the cold so that thieving bread and fruit was all the harder. Florescent gasoline stations lit an entire street so that sneaking close was nigh impossible. And every store had a burglar alarm so that they risked being caught on a security camera if they tried a smash and grab.
"We're out of food," Raphael said, crossing his arms. "You better not be holding out on us."
"You mean holding out on you," Leonardo said.
Raphael huffed. "Don't start that again. I do not eat everything—"
"Not for lack of trying! I said we should steal more—"
"We ain't thieves—we only steal 'cause we gotta and—"
"Oh, and all those arcade games just stole themselves—"
"That place was run by a mutant mosquito that tried to eat us—"
"Well, in a few days, you'll probably eat all of us."
"Leo—"
"Just...I'll share what I have with Mikey—"
Raphael growled.
"With Mikey, not you! You just keep worrying about feeding yourself...like you always do."
Light from the streetlamp came through the gutter, filtering a dim gloom through the tunnels. Something shrieked in the dark. He looked up and saw a dozen eyes glinting at him, coming into the light. A handful of rats, their fangs bared, and as they came closer, he saw that they were all grotesquely large—more than capable of devouring him if he fell.
His stash of food lasted all of two days.
In their latest food run, Donatello had to destroy the cameras and then find the security tape in the store while the rest of them shoved as much as they could into pillow cases. Michelangelo cleaned out the store's candy stash and soda cans and Raphael took all the packaged food he could grab. To his credit, he carried like seven bags in each hand. Leonardo grabbed every bit of rice and all the cans he could, stuffing what he could in his shell to save for himself and his little brother.
The food was gone in a week. His second stash didn't last a day.
The rats leaped. He caught the first one and slammed it down onto the concrete. It stopped move, but the second and third were on him, biting deep. Crying out, he had to catch the fourth out of the air and whack it against the wall, dropping it as it shuddered. He slammed his shoulder against the concrete, dropping one of the biters, but he had to violently tear the second one free, sending blood down his shoulder as it scraped and bit his hand.
It screamed. It didn't want to die and knew death was coming. Its struggles grew panicked and still he beat it on the floor once, twice, three times, until it finally stopped moving and the bones of its body shifted brokenly in his hands. His bloodied hands.
Not bloody for long. He licked them clean. Licked the wounds in his shoulder and arm.
Not a drop wasted.
"Please, just one more food run—"
"It's too dangerous," Splinter said, and Raphael stood at his shoulder. "The late night news has reported on each of your targets. If you go out again—"
"If we don't go out, we're gonna starve," Leonardo said. "There's literally nothing down here—"
"Now why don't I believe that?" Raphael said.
"You think I have some endless cache of candy?" Leonardo demanded, waving one hand at the lair behind them. "Even if I did, it's gone. There isn't anything left. I'm on empty, Raph, and some of us aren't Goldilocks eating every bit of porridge in the house."
"That ain't fair—"
"Enough," Splinter said. "We are all hungry. We will simply have to tough out the rest of the week before we can replenish our stock. Until then, no one leaves, for your own safety."
There was no arguing, not with both of them together. Leonardo scowled and turned away, heading back upstairs to his room. On the way, he passed Michelangelo's door and spotted his little brother on the bed, curled up, arms around his waist, crying.
Leonardo winced. His metabolism worked so fast...
From his shell, he drew out the last remnants of his final stash of food, a poptart that was mostly crumbled bits in its bag, and tossed it on the bed beside Michelangelo. He sat beside him, arm around him, listening to the snack devoured so briefly.
Two days later, when they were chewing ice to try to feel like they'd eaten something, Leonardo called in a favor from his little brother.
It was easy for Michelangelo to fake being sick as a distraction. And Leonardo slipped out into the tunnels.
The rest of the eyes in the dark faded, leaving him alone with the pile of his kill. Kneeling, he bent over them and took one up, tearing its fur down the middle with his bare hands, pulling the skin free. Then he turned the carcass over, examining the muscles and sinew attached to the bone.
And he dug his teeth into the meat, driving down until he hit the spine, scraping up mouthfuls of slippery, wet, hot flesh.
This was the third one he'd eaten that night, with the promise of more at his feet. Squatting comfortably, he felt the edge of hunger fade with every mouthful. It slid down his throat almost as warm as if it had come out of the oven. His hands stank with the coppery scent, and when he was done, he washed his hands in the frozen water spilling from the gutter.
And started on the next body.
When the beams of flashlights came around the bend and focused on him, he didn't stop. His brothers stood silent. He didn't imagine what he looked like. He didn't care. The hunger was finally almost gone. He glanced out of the corner of his eye.
Raphael looked sick. Donatello had turned away, but he studied the other dead rats with a curious eye. He'd been the one to discover they could eat pigeon eggs, after all. And Michelangelo...
Leonardo held up one of the rats for him, motioning him over.
Raphael tried to stop him, putting his hand on their brother's shoulder, but Michelangelo shrugged him off and came to sit cross-legged beside Leonardo. He mimicked his motions, tearing the fur free, looking for parasites, ignoring the entrails in favor of biting out chunks of the back and shoulders.
And they both smiled around great smears of blood.
Only when they were finished with the bodies, only when Michelangelo asked if they could do this again and Leonardo nodded, did they finally agree to go back home. As if nothing had happened, they brushed their teeth and went to sleep, Michelangelo curled in Leonardo's arms on the sofa.
The next night, the lair was full to bursting with the food Raphael brought home in several trips. And he didn't start eating until he saw to it that his siblings had started first. If Leonardo stole whole armfuls to hide away, Raphael didn't complain. He even helped cart the candy bars up to Michelangelo's room.
And no one said anything to Splinter.