The variant I'd heard is shrimp sewn into the hem of the curtains.
Even better, because while they may not take the curtain rods with them after the smell forces them to move, the probably will take the curtains. & bonus, bc it'll contaminate everything else that's packed in the same box.
This must be some sort of Tradition then, I think. I think the variant I saw was on Oprah or something.
A truly horrifying prank I have heard of but never seen actually done is to take out a bicycle seat and stick a hotdog in the seat tube so it slowly rots.
This is like a far less disgusting version
@fesshole To be fair, it's an old MG, will they notice?
"They all do that sir".
The usual procedure I'm familiar with is put a small ball bearing in hubcap.
Ah! Excellent point!