The phrase "Danny already FC'd this" was first used in mid-2009 when Guitar Hero forms and Danny's subscribers on YouTube crowned him the best at Guitar Hero in the world. Soon, after an FC has been posted on a persons channel, someone would respond to the video with: "Danny already FC'd this". Because chances are, Danny has FC'd that song. Jameslikecoulter has parodied this phrase many times in his rants and FC's. Now-a-days, the phrase has become quite annoying and the Guitar Hero/Rock Band community hardly uses it anymore. Some still though.
Person-A: "Yo' did you hear, deadhead6391 FC'd 'Dark Matter'!"
Person-B: "Yeah, Danny already FC'd this, and the harder version of it. Plus, there's way more harder songs than that."