In some European countries, mine included, and perhaps some non-european countries, one of the tradition on the 1st of April is for the children to attach one or several paper fishes in the back or their relatives and/or friends (and teachers sometimes tbh) without them noticing it. Just some innocent joke that doesn’t want to make any harm and a nice way to have fun.
I remember particularly the day before the 1st of April and how as a kid I was making my own paper fish, knowing I’d have a lot of fun the day after and trying to have the most beautiful fishes of the whole school.
I find this far better than the jokes we can make as grown ups and that can sometimes be harmful. So here are two cute suprise fishes, not on your back but your dashboard. Bet you didn’t see that coming, heh? ;)