Often used as a gay joke to guys or an insult to a whore who is always sucking dick.
Also relates to the phrase "gobble the knob".
Just in case you don't know, : knob
Guy 2: what a knob goblin
Girl 1: that wasn't very nice
Guy 2: shut up, you're one to, literally
Girl 1: ...
Guy 2: kthxbye
2) The porn alter-ego of Spideman's nemesis.
Rural usage: "Damn boy, whoooeee! That Knob Goblin sure smoked The Whole Ten Yards and good!"
Comic book usage: "Spidey sure didn't stand a chance against the Knob Goblin. His weapons are fierce!"