Apparently this term originated from a website called RPG.net and from a user that is now banned, Danth. Danth claimed to have won a forum argument, and someone else later said in that forum that, "If you have to insist that you have won an internet argument, you probably haven't."
"I totally won this forum argument-"
"I invoke Danth's law, biatch!"
":("
by Press X To Bonetown March 3, 2015
Get the Danth's law mug.