During secondary school I managed to convince my "friend" Chris Mckenna that bleeding out of your arse was the first sign of puberty and that everyone goes through it.
At first he was very doubtful of this, until the scale of this prank escalated, and after myself and half of the school year pestered and prodded him about him not bleeding out of his arse he finally succumbed to the immense peer pressure.
"So, Chris, you haven't bled out of your arse? That means you haven't started puberty yet. Are you sure??"
"Steven, I meant to say.... I HAVE bled out of my arse."
What a numpty.