In fanfiction, they could be best friends. They might share secrets, like which baby food is the best or where the coziest napping spots are in the nursery. They support each other during the various baby - related adventures they go on, like trying to figure out how to make the crib toys work better.
They could also be like siblings. Staci might be the more cautious one, while Theodore is a bit more adventurous. They bicker sometimes, like siblings do, but in the end, they always have each other's backs. For example, if Theodore gets into trouble for climbing too high on the baby gym, Staci might come to his rescue and then scold him for being so reckless.
In 'The Boss Baby' land, Theodore and Staci were always up to something fun. One afternoon, they heard about a mysterious music box that played the most beautiful lullabies. They made it their mission to find it. They asked around the nursery, but no one seemed to know where it was. Theodore remembered an old baby rhyme that might have a clue. He shared it with Staci, and together they deciphered the riddle in the rhyme. It led them to a dusty corner of the attic. There, they found the music box. When they opened it, the sweet lullabies filled the air, making all the babies in the nursery feel calm and sleepy.
The baby could have a really interesting relationship with Klaus. Since Elijah is Klaus's brother, Klaus might be both protective and a bit jealous of the baby. He could see it as a new addition to the family that he needs to look out for, but also as someone who might take away some of the attention from him.
Their relationship could start with mutual curiosity. Stacy might be intrigued by Boss Baby's strange behavior and Boss Baby could be interested in Stacy's normal, yet kind - hearted nature. Then they gradually become friends as they share experiences.
They might have a baby that has a combination of their physical features. For example, it could have Foxy's red fur and Mangle's long limbs. Maybe it also has Foxy's eye patch on one eye and Mangle's multiple tails.
In this fanfiction, they might have a very close and protective relationship. Since they are sisters, Bella could be always looking out for Elena, and vice versa. They might share secrets, support each other through difficult times, and be each other's confidantes.
Another possibility is that the baby has a combined power. It could use water to create illusions, a mix of Percy's water control and Annabeth's strategic thinking. So when in a fight, it could create false images of itself using water to confuse the enemy and then attack from an unexpected angle.
The baby could have the power of compulsion like Klaus, being able to influence the minds of others. Since Elena was a vampire too, the baby might also inherit enhanced strength and speed.
The baby could inherit Soul's coolness. Maybe it would be a laid - back baby who is not easily flustered. Or it could have Maka's determination. So when it wants something, like a toy, it would be very persistent in getting it.
The baby could potentially have Naruto's chakra powers. Since Naruto has a vast amount of chakra and can access the Nine - Tails' power, the baby might inherit some of that. Maybe it could also have some unique abilities from the OC. For example, if the OC has a special type of jutsu related to nature manipulation, the baby could have a combined form of that and Naruto's powers.
The baby might be very inquisitive. With Athena as its mother, it would inherit a thirst for knowledge. It could constantly be asking questions, eager to learn about the world around it, whether it's the secrets of the ocean (from Percy's side) or the wisdom of the heavens.