When they learn they're going to be facing off against a boggart for revision the class seems to stutter, because not only is it terrifying to see your worst nightmare, it's also in front of people.
There is also a very particular timeframe in which you're legally allowed to demonstrate boggarts to children because they need to be young enough that their problems are still clowns and spiders but old enough that they can deal emotionally with it. At sixteen this is definitely pushing it.
Remus is already hidden at the back and James shoves Sirius over as well because in third year it turned into a half-eaten James and a blood-splattered ritual room respectively. Hopefully since it's such a big class they won't get around to the last few.
This year it's a class combined with Hufflepuff, so even while they practice saying the spell the 'Puffs are looking at the Gryffs and the Gryffs are looking at each other to see who will go first.
James, because of course he does, situates his friends far away and struts right up to the front of the class with one hand on his hip and the other spinning his wand until it's a blur. "Did you name the boggart?" he asks the professor.
"I'm not in the habit of naming boggarts, no," she replies, amused.
"Can we call it Lucy?" James continues. "I bet it looks like a Lucy."
The professor smiles. "Alright then, class, line up if you will, single-file in front of Lucy's trunk."
James does a little fist pump.
The professor stands far enough away she won't interfere with the boggart's tracking and flicks her wand to open the trunk. A great plume of hazy smoke blasts out and locks onto James, cycling through forms too quick to see properly.
James waits with a little bit of anticipation because he's curious what his form will be.
In third year, they'd just had the Minister fiasco in the Great Hall so his form was Azkaban because he was still pretty sure they'd shove him into jail and he'd have to wait until Sirius and Remus broke him out.
Maybe being alone is his fear, since they really are a bit too co-dependant (and James craves constant, unwavering attention like he'd drown without it) but no, James can't think of a single reason he'd ever be alone so it's hard to be scared of it if he can't even conceptualise the thought.
Perhaps of his friends dying? But what could pin down Sirius, who can apparently break out of Azkaban and travel through time if he wants it hard enough, who James knows has something strange inside him, something a bit mad and a bit sharp and maybe not undefeatable but certainly unbreakable.
Remus, stronger and faster, magic resistant and clever - well nothing could hurt Remus unless he's doing it to himself. Harry fought a Dark Lord and won, even if someone got him in the back with an avada, he'd probably pop right back up again.
So James watches the boggart shift, thinking he'll laugh it right back into the trunk even without a riddikulus if it turns into darkness or scary monsters and other cliche fears.
A part of James, a small part, thinks of a mirror image, head high and eyes bright like there's a whole crowd cheering just for him, like he owns the ground he walks on, like this is a performance. But no, he's not afraid of people knowing who he is. Everyone that matters already understands and all the others can get out of his way.
The boggart settles into something that could perhaps be called a form, splatters over the ground, surges in a jerky motion like a seizure, too many grotesque, thick and double-jointed spines flailing.
The class scrambles back as the boggart swells, bony sections like a ribcage showing through as it inflates and spreads small, thin fungus-like webs over the ground at a rapid pace.
"Wow, okay, that Czech manor really traumatized me," James laughs nervously.
The defence professor steps forward and - listen, okay, James is really creative and his imagination is boundless but that's not really a positive thing right now because all of that cleverness is being put into how to best murder the entire class since he can't really stop himself from thinking about it.
So the professor steps forward but the boggart is already locked onto James -the way James worried it would be able to, with more of its mass closest to him- and the boggart lashes out with a sharp-tipped spine moving like a spider's leg and pierces straight through the professor's shoulder because she's the greatest threat and James -the boggart- needs to take her out first.
The students are screaming, the professor is lifted into the air, more spines lash out at the audience and the fungi network is crawling up people's legs and sealing the windows and doors shut.
This isn't so poetic, it's not an exact mirror of James but it is him, killing all these people because he just can't stop himself, can he? This is James, going too far like he knows he does sometimes, uncontrolled and ugly and unlovable.
"You don't half-ass this shit, do you?!" Sirius cries, pulling out his wand.
"I have an overactive imagination!" James wails and sets some fungi on fire - but he'd already thought of fire to protect himself so of course the monster would be fireproof because it wouldn't be scary if James could get rid of it with a flick of his wand.
James tries to raise occlumency shields but while it can prevent a boggart from locking onto you, it can't cut one off. Students are hurling spells at it but James already thought of that and so the monster is magic resistant.
Lily steps in front of James so the boggart changes form but it's scary enough to become most people's greatest fears now so stepping in front doesn't actually change it and instead fuels it.
"I'm sorry!" James tries, attempting to transfigure it but the almost gelatinous, fleshy mass falls out of shape again with its elasticity because if James could transfigure it into a tiny teacup pig then it wouldn't be his greatest fear. "I'm really sorry, I think it's indestructible."
The professor is thrown into the wall and she hits the ground already unconscious. A Hufflepuff gets stabbed in the thigh and he's dragged towards it screaming, a Gryffindor just barely dodges and gets her arm cut up the side, and someone barely tackles another girl out of the way of an attack.
Remus is working on taking down the classroom wall instead of competing with the insanity that is a manifestation of James' mind. Except the fungi is growing up the walls and forming a blockade because James already thought of taking out the walls to escape.
"Oh Merlin, everyone's going to die," James realises.
Sirius grabs James' shoulders and spins him around so he isn't looking at the main mass, though he can still see the fungi network and the shadows of joined spines on the walls.
"Jamie, am I powerful?" Sirius demands, grip tight and eyes narrowed to flecks of dark slate grey.
"Of course," James agrees.
"The most unbreakable person you know?" Sirius demands. "The absolute best?"
"Wha- yes, you are. Should we be talking about this right now?"
Sirius spins James around and holds him facing the boggart. "More than that thing? Am I the most invincible thing you could ever think of?"
"I - well..."
"I better fucking be or else I'm going to be pissed," Sirius growls and hurls a spell through the chaos. "Bombarda maxima!"
The boggart explodes, a huge tear ripped through the side and some spines collapse in on itself. It's only as strong as James can make it, and in his mind Sirius has always been stronger.
James slumps back into Sirius' chest. "Fuck, Harry could probably look at it sideways and it'd disappear."
"Remus, us two can kill it because James is a little softie!" Sirius calls out.
"Rude," James says and gets shoved off so Sirius can roll up his sleeves and get stuck into it, soon joined by a confused but willing Remus and they both manage to cut enough bits off that the boggart reverts and they slam it back into the trunk.
"Guys, I'm really sorry about that," James says apologetically to the tired, traumatized and bleeding students. "I...have some issues I need to work through."
"Go fuck yourself!" snaps back a Hufflepuff girl. "You nearly killed everyone - half of us need the hospital wing!"
"Just because he has a little Merlin damned creativity!" Sirius barks back. "Take your basic bitch fear of heights and shove it up your dick you pathetic fuckface!"
The Hufflepuff rears back but gets stopped by her fellow housemates because, well, it's not actually James' fault that he's scared of an eldritch horror.
James feels a little bit better but still sadly edges around the room to Sirius and Remus, who fold James into them when he arrives, arms coming around so they make a little huddle.
Remus tips down a bit and pressed their foreheads together even when James' glasses are threateningly close to his eyes. "You just gave me a new boggart."
"You can have it," James grumbles, pushing a bit deeper into their chests and plucking at Remus' jumper.
"You want me to scare you enough that you get a new one?" Sirius offers.
"Yeah?"
"Dead Harry," Sirius lists. "Murdered Harry. Murdered Harry in a horrific, torturously long manner. Dead parents because they die of dragon pox in only a few short years. Dead Remus because you die and I go to jail so he slowly tears himself apart every full until he's so lonely and depressed that he actually starts to fear the moon again. Dead me because my parents crucio me to death when I try to leave-"
"Okay!" James cries, grabbing Sirius' face in both hands. "Alright, fuck, wow. We can stop. You can just - not. Not say another single fucking word, fuck me. Okay then. That's fine, haven't had nightmares in a while, I missed them."
"You're welcome," Sirius mumbles out, lips squished from James' grabbing.
"Now that James is sufficiently upset, we should help heal the others," Remus says.
"Lily!" James cries in shock as he does a double take after glancing around the room. "I didn't even see you get hit?!" Not unsurprising though, with the way she threw herself into the thick of things.
Lily is standing with a hand over her heavily bleeding side, top and part of her skirt soaked from all the blood, a grimace on her face. "Well I certainly felt it."
James rushes over to play medi-wizard with his moon-necessitated healing knowledge and the other two put their hands together and break like quidditch players before darting off as well.
James doesn't actually get into trouble for almost killing a whole class but he does get sat down while Pomfrey gives him a long talk about mental health and being mature enough to ask for help when you need it because that's what friends/parents/anonymous owl mail/professionals are for.
James ends up sending a letter to Tom during their weekly Voldemort-enforced correspondence about his new murderous boggart almost killing everyone. Tom sends back sarcastic heartfelt praise for James finally coming into his own as a budding danger to society.