This is referring to goofy from the show mickey mouse. Goofy is usually messing up things before anyone else has the chance to do so themselves. This may sound like a formal explanation but this phrase means of nothing formal at all. In conclusion, to beat the goofy out of someone would be kicking there butt until they actually believe that they cant mess up anymore because they have no goofy left in them.
by Db leedtthj December 23, 2016