
Think about it: Casper the Friendly Ghost is really creepy. Not for the whole “wanting to be friends with people” thing, or even how the guys on Cheers observed that Casper must somehow lose all his friends between cartoons, or that one really warped episode where Casper befriends a fox pup that gets killed, only to have the fox’s ghost show up to immediately pick up where it left off with Casper (that’s some demented stuff right there). No, the fact is Casper is a kid, always will be a kid, and he’s a ghost hanging around for some reason. That’s some prime potential horror right there.
That sort of thing was realized a bit better with Secret.
Secret first appeared in a Young Justice special. She seemed to be a girl made entirely out of some kind of mist, trapped by some scientists. Robin, Impulse, and Superboy rescued her from a lab and she eventually became one of the original three female members of the team alongside Wonder Girl and Arrowette. No one quite knew her deal at first, or even her real name. Heck, she couldn’t remember her real name. The others called her Suzie.
Early on, though, the team ran into a young wannabe supervillain calling himself Harm. Harm actually died fairly quickly, which didn’t end his villainy, but there was one little detail from his past that was somewhat important. See, to prove how evil he was, Harm has murdered his kid sister Greta in a way that caused young Greta’s soul to be stuck between worlds.
Hey, three guesses who Greta was!
As “Secret,” Greta/Suzie had your standard ghost powers. She could pass through solid objects and fly. She could also use her mist to change shape. And due to her unique status, she also acted as a gateway between the living world and the afterlife.
And that’s where problems started. Being stuck that way meant Secret had a really dark side she tried to keep in check, with so-so success. Secret had a crush on Robin. This would become something of a problem because Robin was dating another teenage hero going by the codename of Spoiler, and let’s just say Spoiler had the occasional creepy run-in with Secret.

During a fun “Sins of Youth” storyline, when Klarion the Witch Boy switched ages on different heroes, making the adults kids and the kids adults, a now grown-up Secret managed to get everything switched back by threatening the life of Klarion’s cat Teekl. And the threat was good enough to get Klarion to act…which actually made Secret more miserable because she was at least temporarily an adult, and, as a ghost, she’d never grown up otherwise.
See how creepy Casper is?
Secret needed guidance. It didn’t help that her dead brother Harm possessed the body of their father and made the man repeatedly tell Greta how unwanted and evil she was, hurting her even more (seriously, Harm was one of those bad guys who readers like me really wanted to see get a good smack once in a while). Seeing most of Young Justice had mentors, an arrangement was made for Secret to have Hal Jordan as a mentor seeing as he was the Spectre at the time.

It actually turned out the mentor Secret really wanted was a guy she called Doug. As in Doug Side. As in Darkseid. Eep.
As it was, Harm was destroyed by falling into a firepit with his possessed father and Robin talked Greta down. Disappointed, Darkseid took away Greta’s powers, saying that by making sure she wasn’t special anymore, she’d be be dull and ordinary.
Of course, when you take away a ghost’s powers, you essentially bring them to life, so Darkseid’s “punishment” was actually what the girl wanted all along.

So, unlike Casper, her story turned out much better.