In my last campaign my son played a gnome fighter and during PC creation he specified he wanted to be in the middle of a prank war with his NPC cousin. So throughout that campaign, Binkadink Dundernoggin and his cousin Jinkadoodle were constantly going back and forth with their pranks. It started in the very first adventure, when Jinkadoodle (an illusionist) planted a magic mouth spell on Binkadink to make a farting sound when he spoke in front of the king. Further escalations between the two of them involved sovereign glue on a puzzle box, magic mouth spells on potion vials that spoke rude phrases in the voice of the imbiber, sovereign glue on the seat of the pants adhering Jinkadoodle to the helm of a spelljamming vessel, an illusion spell making it look like Binkadink was having some "special naked fun time" with a goat in a stables, and Binkadink using a hat of disguise to make him look like a naked Jinkadoodle streaking through the crowded marketplace, complete with baby-sized genitalia and a hat emblazoned with the name "JINKIE" in case anyone might have had any doubts about who to blame.
Of course, Binkadink didn't reserve his pranks for just his cousin. He made ample use of his gnomish prestidigitation to frequently turn one PC/NPC's hair (or the fur of an animal companion, including his own jackalope steed) into a wild and vibrant color for an hour (starting with himself as the first "victim," to allay any suspicion), occasionally pairing that prank up with a ghost sound of mischievous laughter to the point the PCs were convinced for months they were being stalked by invisible pixies. He also once used prestidigitation to change the scent of an ointment the wizard was placing under his nose right before entering the sewers; by changing the smell of the ointment to that of feces he had the wizard convinced he'd been swindled by the ointment salesman.
Johnathan
