Prompt idea: an ectoplasm is kryptonite AU where ghosts are radioactive to Kryptonians, with a Dani/Kon forbidden romance where being together is literally killing him. He’s “fine” when she’s in human form, except for when she uses her powers. “Fine” in the same way that someone allergic to cats is when in a room where a cat lives but it isn’t present. Aka not actually fine but putting up with it. He’s just getting low doses of radiation poisoning all the time. Because Dani/Ellie is basically made of liquid kryptonite. Being together means both of their powers are null. Hers by choice, his by proximity.
Consider: If ectoplasm is Lazarus water, then Superman has been revived by the Lazarus Pits, so it's not always lethal. Maybe it can be rejuvenating under certain circumstances, such as when on the brink of death. A way for them to be together might be Kon gets mortally wounded (because he’s vulnerable when near Dani? That adds some fun angst) and rather than clone a new version or get him to a pit, Tim and Dani break into Vlad’s lab and stick him in the ghost portal and turn it on, resulting in a half-Kryptonian halfa.
