Give a gift card to someone, with it in jail! A great prank to make it harder for your friend (victim) to open their gift card. When it's printing, drop the gift card in before the extruder gets to the top bridging layers.
If printing directly to Bambu Studio from Maker World, the 3MF file is sliced to automatically pause printing before it gets to the top, so you can drop the gift card in, just press resume on the printer after you drop it in.