A Bitch

Damian doesn't know who Santa Claus is and Danny tries to gaslight him into believing in Santa

Okay but, like, wouldn't even be gaslighting! Santa canonically does exist in the DC universe, I think I remember reading something about him fighting through an army in hell to give Darkseid a single piece of coal once?

So like, Danny doesn't have to gaslight Damian into believing Santa's real, he just has to pull out the proof (Danny has a binder of everything he knows about the Spirit of Christmas for the purpose of when he eventually goes to war with him, Danny hates Christmas so fucking much haha) and show him evidence that Santa is real.

Probably ranting the entire time about how much he hates the guy & Christmas and it's obvious that this is Danny's arch nemesis. His one true villain above all others. Pariah Dark? A nuisance. Dark Dan? Just a tuesday. Santa? That motherfucker is the bane of Danny's existence and he will pay for what he's done (spread Christmas cheer).

And Danny's the newest member to the family. Damian's been encouraged to get to know his new brother and try and bond with him a bit, make him feel like part of the family. So, obviously, the best way to do that is to help Danny in his quest for vengeance.

And of course Tim & Jason end of getting roped in on this. Damian's grown since he's first came to live with his father. He still is a little brat to his older brothers - he's the baby of the family it's his right - but he doesn't actively hate them anymore and can admit when their particular skills would be useful. Tim is the best at strategizing, and Jason is a combat master with access to all sorts of weapons. With all of them working together Santa has no chance, they will destroy him.

Which all just makes me think of something like this happening lol:

“What…uh, what are they doing?” Duke glanced between the chaos unfolding in the family room to where Dick was calmly seated in his favorite chair, sipping idly at a cup of coffee.

“Sibling bonding.” Dick said. There was that specific aura of calm around him that said that he’d already gone through several crisis and all the stages of grief at least twice. Considering the calamity and chaos the eldest batkid had seen over the years - and especially the last few months since Bruce officially adopted Danny and brought him into the fold - it was a bad sign that he’d reached this particular state of Done (TM) before noon. The earliest Dick even woke up was two in the afternoon.

Duke contemplated turning around right then and there - the particular combination of people all excitedly feeding off each other’s feral energy on the other side of the room was a catastrophe in the making he didn’t want to be anywhere near when it finally breached containment and spilled out into the wider world - but unfortunately he was cursed with the curiosity that afflicted all members of the bat clan.

“It looks like they’re plotting to try and kill Santa Claus.”

Dick turned to look at Duke fully for the first time since he’d entered the room. He had the eyes of one that was deeply haunted by the horrors they had witnessed. On the other side of the room Tim was ranting about anti-magic tech while Danny, Damian and Jason argued over what weapons would be most effective against a demi god. There were schematics of what looked worryingly like a rocket launcher looking device that - if the scribbles on the whiteboard someone had drug into the room where to be believed - was going to be rigged to shoot ecto-grenades.

“Danny hates Christmas.” Dick said, and Duke noticed for the first time that his hands around the coffee cup were faintly trembling. “He’s declared Santa is his arch nemesis.”

Duke blinked, glancing over to the others long enough to see Danny start frantically scribbling the words Christmas Nuke on the whiteboard. No one else was trying to erase it. Tim looked worriedly contemplative. Damian and Jason where both nodding in agreement.

He was going to regret this. “But Santa isn’t real?”

Dick’s eyes gained a faintly manic glean, and Duke could faintly hear the sound of porcelain creaking warningly beneath the desperate hold he had on his coffee cup. “That’s what I thought!” Dick said, with enough cheer to make Duke flinch back instinctively. “But apparently he is.” A distinct crack appeared in the cup, coffee dripping down into Dick’s lap. “And apparently they’re going to war with him!”

Well, Duke considered, at least that explained why he caught the four of them burning down the giant Christmas tree in the city center last night.