Peter could play a really funny prank on the Avengers. He might use his agility to secretly attach some helium balloons to Captain America's shield. So when Cap tries to throw it, it goes all wobbly in the air because of the balloons. And for the Hulk, Peter could create a holographic image of a really cute kitten right in front of him. Since the Hulk is usually associated with destruction and anger, seeing a cute kitten would be a really unexpected and humorous situation.
In this fanfiction, Peter might use his quick wit and spider - powers to play pranks on the Avengers. For example, he could use his web - shooters to move things around in a way that confuses them or set up some harmless traps. It could be really funny to see the Avengers' reactions to Peter's childish yet clever pranks.
Well, there's a fanfic where they prank Carlisle by making his office look like a disco. They put up disco balls, flashing lights and played really loud disco music. It was hilarious. Also, the prank where they switched Rosalie's beauty products for really cheap and smelly ones. Rosalie was so angry and her reaction was quite memorable.
In the 'Harry Potter Pranks Everyone' fanfiction, there could be some hilarious pranks. For example, a student might use a charm to make the Great Hall's ceiling show embarrassing memories of the teachers. Another prank could be to magically swap everyone's voices, so that when they talk, it comes out as someone else's voice. There could also be a prank where the Hogwarts Express gets diverted to a completely different location, and the students end up in a strange magical place full of odd creatures and unexpected challenges.
Well, in some fanfictions, Naruto has been known to put salt instead of sugar in Sakura's tea. She takes a big sip and spits it out right away, which is quite funny. Also, he might play a prank where he makes it seem like Sasuke has a crush on Sakura by leaving fake love letters from Sasuke around. It causes all kinds of chaos and blushing between the two of them.
Maybe Naruto uses his shadow clone jutsu to create a bunch of clones that keep following Tsunade around, asking her silly questions all day long. This would drive her crazy as she tries to get her work done. For example, they could keep asking her about her love life or her opinions on the latest ninja gadgets.
A really funny prank could be where a student's quill is jinxed to write only in limericks. So when they're trying to take notes in class, instead of normal writing, it comes out as comical rhymes. This can be a source of great embarrassment, especially if they don't notice right away. Also, pranks with vanishing ink on important parchments are quite common in fanfiction. The victim thinks they've written important information, but it all disappears, leaving them frustrated and others amused.
A really engaging plot point in some 'Naruto pranks Orochimaru' fanfiction is when Naruto involves Orochimaru's henchmen in the pranks. He might trick them into believing that Orochimaru has changed his orders or is planning something different. For instance, he convinces them that Orochimaru wants them to build a huge, elaborate structure for no real reason. As they work on it, Orochimaru gets confused and angry when he sees what they are doing. This creates a lot of comical situations as Orochimaru tries to figure out what's going on and his henchmen are just following what they think are his orders.
In the fanfiction, Naruto might prank the Anbu by replacing their normal kunai with ones that make really loud and embarrassing noises when thrown. So when they go to use their weapons in a serious situation, they end up looking foolish as these noisy kunai fly through the air.
In certain 'dumbledore gets pranked fanfiction', a popular prank is to make Dumbledore's office furniture float and move around chaotically. Imagine him trying to sit at his desk and the chair keeps scooting away or the desk starts doing a little dance. Also, there could be a prank where his glasses show false images, like seeing a dragon in the hallway when there's actually just a cat.
One of the pranks Naruto might do is to mess with the Anbu's communication system. He could use his knowledge of chakra and some basic electronics (if we assume some modern - like elements in the fanfiction) to scramble their signals. This would make it difficult for them to coordinate with each other, and they'd be running around trying to figure out what's wrong while Naruto watches from a hiding place, having a great laugh.