#Phantom and Batman will eventually meet in the future due to ghost shenanigans

[tryoncami]

Danny had been Phantom for all of two weeks before he realized he found a lot more joy interacting with his parents as Ghost hunters than he ever had as a normal teen. He had talked with Sam and Tucker about it, but they had just shrugged it off.

Danny continued to stop the ghosts threatening the town, getting stronger and more skilled until Jack and Maddie introduced the Ghost separater. When Danny had gone through the Ghost separater, he had been shocked to find himself staring at a different version of phantom than the one he usually saw in the mirror.

His mirror image smiled with glee and gave Danny a hug. "It's nice to meet you for real!"

"What?" Danny asked confused out of his mind. "Aren't you the ghost version of me?"

"No silly!" The ghost boy chuckled. "I've been haunting you since Mom took you from your basket in the hospital. I'm the one mom was supposed to raise, but I died during birth. Mom took you from the nursery and raised you in my place. I've been tagging along ever since because I wanted to see how life would have been with Mom."

"Are you saying I'm not really Danny Fenton?" Danny asked breathlessly falling to his knees.

"I guess that's not really your name," ghost Danny said. "It's technically mine. I don't know what your name would be otherwise. I couldn't read when Mom took you. I do know you were a twin though. Mom took you from a crib that had another baby that looked just like you."

Their conversation was interrupted by the sound of Jack and Maddie returning. The two ghost boys turned invisible and phased through the ceiling.

Thomas and Martha Wayne had twins Danny and Bruce. Danny was stolen from the hospital by a grieving Maddie after her child was still born.

The only one who knows is Maddie. Jack was held up in a villain attack on his way to the hospital. Maddie met him at the entrance with the bundle and just leaves with a manic look in her eye and a death grip on the baby.

The couple left town with the kids because they wanted a safer place to raise their kids... not because Maddie became extra paranoid. No not at all.

Bonus:

Phantom is the ghost of Maddie's still born child. He haunts danny because he knows maddie is his mom and wants to know what it would be like to be taken care of and grow to adulthood. They got fused when the portal accident happened. That's why he is ridiculously powerful from the get go. He's a fresh ghost who has been fused with a teen ghost.