hijinks
Playful, silly pranks that cause harmless trouble and laughter.
Hijinks are playful, mischievous activities that cause harmless fun and minor chaos. When a group of friends sneaks around setting up a surprise party, or when kids secretly rearrange all the chairs in a classroom to confuse their teacher, they're engaged in hijinks.
The word suggests pranks and schemes that are more silly than serious. Hijinks might involve some rule-bending, but they're fundamentally good-natured and don't hurt anyone. When your little brother puts googly eyes on everything in the refrigerator, or when students coordinate to all wear the same odd costume to school, that's hijinks. Classic children's stories like Stuart Little and Pippi Longstocking are full of hijinks.
Hijinks differ from serious mischief because everyone (eventually) laughs about them. They're the antics that make people shake their heads and smile rather than get genuinely angry. Teachers might roll their eyes at student hijinks but still appreciate the creativity involved. The word often appears in phrases like up to their usual hijinks or hijinks ensued, suggesting that wherever certain people gather, playful chaos tends to follow.