From the moment that Alec was out of the Institute after those fateful words, Jace and Clary were plotting revenge.
"What about April Fool's Day?" Clary suggested, but the look on Jace's face told her he knew nothing about the holiday. "Right, mundane thing." Clary muttered under her breath, "Okay, April Fool's Day is when people play little jokes on each other, like sticking someone's stapler in jello."
Jace had a bewildered expression on his face as he asked, "Why would someone?"
"That's why," she said, pointing to his face, "for the confusion of it."
"Okay so how do we get Alec back with it"
"Well the classics are the jello thing, covering a room with pictures, uhh, putting a post-it note under a mouse," she said counting off on her fingers as she went, "A bucket of water over their door."
Jace immediately sat up straighter as an idea came to him. "For the water thing, does it have to be water?" he asked with a smirk and a glint in his eyes.
And that was how, twenty minutes later, the pair found themselves inside a craft store looking at an aisle of gitter of various shapes, sizes, and colors; Jace's face practically evil as he rubbed his hands together at all the options laid out in front of him.
~~!~~
Alec entered his office while wondering why his door was open, when a bucket dropped on his head. Not just any bucket, no, the bucket was full to the brim with glitter. What felt like the entire institute stood frozen in abject horror, the silence was only broken by the sound of the bucket crashing to the fragile stillness was broken by Jace's laugh.
Of course Jace would do it, Alec thought, he's been pranking me all day.
"The look on your face!," Jace somehow managed to say through his laughter. "Ahhh, it's priceless!" He was so focused on wiping the tears that were falling down his cheeks, that he didn't notice Alec creeping closer.
"Well if you think it's so funny why don't you have some." Alec jested as he just barely missed Jace as he ducked under his outstretched arms. "I think such an achievement deserves a hug. Don't you?"
"No way in hell." And with that Jace turned on his heel and sprinted down the hallway.
A "Get back here you asshole. It's only fair, we do have a bond after all." was barely heard as Alec chased after his parabatai.
Jace laughed until Alec caught up with him in the middle of OPS, surrounded by their fellow shadowhunters.
"See how you like being covered in glitter, Jace," he said whilst rubbing his hair, and the bulk of the sparkly dust, onto Jace's shirt.
"Hey, It wasn't just me! Clary helped too." the blond said, throwing his girlfriend under the bus.
Alec slowly turned to the aforementioned girlfriend with an eyebrow raised. Clary just flung out her arms to accept her punishment for it.