Jace would later deny it to his dying breath, but the sound that he made when waking up to his room covered in little rubber ducks was more fitting of a yipper dog than a shadowhunter.
Alec knew that Jace would hate him for this, but it was worth it just for the look on everyone's face at the sound that he made.
"WHO DID IT?" Jace boomed as he entered Operations; his hair was sticking up in every direction and his shirt only half way on. No one would look him in the eye as they were too busy laughing still. "Izzy, was it you?"
"Don't look at me, hermano, I didn't do it. Though I wish I did if whatever it was made you scream like that." Izzy was still chuckling as she spoke. "Speaking of, what made you scream like that?"
Jace turned bright red as he realized what everyone was laughing at. Him. He mumbled something under his breath, probably a few choice curse words.
"Enough," Alec said, nothing giving away that he was the one to prank his brother, not a smile, not even an amused tone. "Well whatever it was and whoever it was can be discussed when you are off duty." He shot all of the people in the room a glare before he snapped out a "Back to work."
Jace sheepishly rubbed the back of his neck as he walked closer to Alec. "Thanks for that. Also could we not mention the scream?"
Alec's smirk was answer enough that no, they would not be dropping the scream.
Alec's alarm went off as he opened his mouth to tease Jace. After he looked at the screen he said, "I have a date with Magnus so I have to go, but since you got in pretty late this morning after patrol, why don't you go sleep in my bed while we clean out the ducks from your room."
Jace was so tired, now that the adrenaline crash had set in, that he didn't even notice that Alec knew what was in his room, even though he never said what made him scream
Alec had a rare twinkle in his eye and a smirk on his lips, when he greeted Magnus on their lunch date with a kiss.
"Hey Magnus. How was your day?" He said, ignoring his boyfriends raised eyebrow.
"What happened that has you in such a playful mood?" He asked after pulling away from the kiss. "Not that I'm complaining, it's nice to see you have fun every once in a while."
"Let's just say that Jace had the wake up call of a lifetime," the shadowhunter said with a smirk. After they ordered and sat at a table, he explained. "I may or may not have covered Jace's room in rubber ducks in such a way that they were staring at him when he woke up. He yipped in terror when he woke up." Neither of the two men were able to hold back their laughter at the revelation.
"So you're telling me Jace, big bad shadowhunter Jace, yipped like a frightened chihuahua at the sight of a few measly rubber ducks." Magnus was barely able to finish his sentence, he was laughing so hard at the mental image.
"Oh more like a few… hundred… thousand."
"Alexander," the warlock said in mock scandalousness. "And what did he do when he found out that it was his parabatai that was the one to prank him?"
"That's not even the best part, he doesn't know it was me." A smirk firmly in place on Alec's face as he took a bite of lunch. After he swallowed the bite he continued. "And he has enlisted me to help him find whoever did it."
Magnus was cackling now, head thrown back and his drink absentmindedly paused halfway to his mouth. "Oh Blondie, you have no idea what you just signed up for. Are we going to be pranking anyone else or is it just Blondie?"
"We?" Alec asked with a smile and his head cocked to the side, reminiscent of a particular pet name Magnus had tried.
"Yes darling, we. I do have a few ideas on how to get him back for all those times he was a cock block," the warlock said absentmindedly, already planning out the pranks that he wanted to pull on Jace and even some that he wanted to play on the other shadowhunters in their friend group.
Alec coughed slightly, choking on the sip he just took. "What did you have in mind?" he asked when he could breathe normally again.
"Well for Biscuit it's going to be a process. How easily can you sneak into her room?" Magnus asked. Alec opened his mouth to answer but the warlock cut him off. "Never mind, I'll just use magic for that bit."
"Mind filling in the lost shadowhunter? What exactly do you have in mind for Clary?" Alec asked, a little miffed that he couldn't help prank the one that has been a pain in his ass for a while.
"Now that would be telling, darling," Magnus teased with a smirk and a wink.
His boyfriend gave an unamused eyebrow raise in response. "Who would I tell besides you? I can't tell Jace because he would wonder why you want to suddenly prank his girlfriend." Alec put his forefingers together, fingertip to fingertip, counting as he went. "Obviously, can't tell Clary." His middle finger was now the one being counted. "Izzy's out because she would tell Simon, who can't keep it a secret." Ring finger. "Max already gets in enough trouble without me telling him that I pull pranks every now and then." Pinky. "Do you want me to keep going?"
"I was just teasing Alexander, I was thinking about rearranging her art supplies. Nothing harmful to her craft, just mixing the colors around." Clary was a neat freak methodical when it came to her art supplies. It was perfect. As they finished their lunch, they started to plan out what pranks they could pull on their friends. They didn't care about the clock that was ticking away for hours as they plotted.
"Why is there no footage? There's always footage." he mumbled a few days later. Jace was at his station looking for the prankster.
"Well, who can erase the footage and knows that you're afraid of ducks?" Clary was sitting on the desk beside the monitor. The fact that he's afraid of ducks wasn't something he wanted to admit, not even to Clary, but he didn't have a choice in the matter. Clary would've nagged him until he told her. Not that he wouldn't have told her anyway, he just would have liked to tell her on his own terms.
"Plus someone's been messing with my art supplies. Even after I locked the door, they would still be messed up. This morning I forgot my necklace and after I unlocked it, they were messed up again. I was gone for maybe thirty seconds, but no, poof they were messed up." At that Clary furrowed her eyebrows "...As if by magic. Jace what if it's not someone but some people? Think about it, who can get into your room, knows about your fear of ducks, and can easily ask a warlock to mess with my art supplies. And if it's not Izzy," Clary trailed off, not wanting to ruin the surprise for him.
Jace had a bewildered look on his face. "But the only one left that can do all of those things is…" Clary practically saw the lightbulb go off over his head. Jace's shoulders tensed and his expression soured as he thundered his parabatai's name. "Alexander Gideon Lightwood! You bastard!"
Alec took one look at his parabatai marching towards him, and promptly burst out laughing. "Took you long enough to figure it out."
"Took me long enough? Took me long enough he says!" He picked up the closest thing in his reach, a stack of post-it notes, and threw it at Alec. "No wonder you wanted to help me figure out who did it. You wanted to get me off your tail."
Easily dodging the thrown paper, Alec, through his chuckling, said, "You're the one who roped me in to helping you." He dodged the various projectiles that Jace continued to throw. "It's not my fault that you were the one that didn't think that I was one of, like, five people max that knew that secret."
"Oh, now it's on Lightwood. I'm not about to let you get away with this. This means war."
Alec smirked and shot back a "Bring it, Herondale"