The character Jim Halpert uses from "The Office" to fuck with Dwight Schrute during a customer sensitivity drill over the phone in front of Michael Scott.
Jim Halpert: Hi, This is Bill Buttlicker and I'd like to buy some paper.
Vicious creatures that attack your butt endlessly. Usually, the only treatment is to burn them out with a lighter and some flatulence. These little critters are usually transmitted by someone who's alias is BewareOfButtlice. He keeps them in a jar. They respect him and follow his orders. Avoid BewareOfButtlice at all costs.
A word that pertains to someone or something that "kicks butt".
However, recently, the word has devolved to be used as a noun, adjective, verb, and even an idiom. In reality, buttkicker is simply the grammarically incorrect way of saying "kicks butt".
Sam: When your friend tries to make good roasts but then ends up failing: buttkicker.
Tom: STFU Sam you degenerate that isn't how you say it.