There used to be a glitch in Minecraft where when the Ender Dragon was doing the dying animation, you could exit and come back in, only to see her flying in circles.
"WHY DOES IT WORK?"
the dying enderdragon doesnt actually have a death animation, but it needs to so it just flies in circles, the first animation. and when you come in and out it cant load no animations so it does animation 1
"WHO DISCOVERED IT"
me, i think