Pardon me miss, I'd like to take a stab at explaining it to you.
Supposedly it has something to do with the vernal equinox celebration beginning March 25th and ending April 2nd. So the last day of the celebration, it was decided that pranks and hoaxes would be played.
Sounds like a pack of bullshit to me but eh whatever. I just try to keep my head down and my nose clean.