Fanfic concept(Dead on main):
The ghost king finds himself lonely after so many years of ruling, so he intrudes a nearby gala hosted by a rather infamous man named Bruce Wayne. There he masquerades as Danny Fenton, whom he usually refers to as "a relic of my past", and finds a connection with the second eldest son of the family, Jason.
He senses the same experiences of death and rebirth between the two of them so he wastes no time chatting. At first Jason is wary of Danny, thinking that he must be the son of a business man trying to butter him up .
But it doesn't take long for Danny to sway him through charm and shared interests(They're both nerds is what I'm saying)
Soon the final dance comes along and of course they partner up. As they dance though, the lights start to dim rapidly. Bruce gets news that the tech in the building was starting to lag/fail on them.
Then the room turns dark except for a single spotlight on the couple in the center. As they spin, the ghost king's true form is revealed, snow white hair and glowing green eyes. He leans in and whispers a vow to Jason, asking him to accept it.
Despite Bruce's best efforts he's unable to reach his son before Jason agrees and they dissappear together. The lights finally turn back on. Jason Todd was gone again.