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a large gathering of birds that fly across the runway just as you start your takeoff run.
Co-pilot, "BIRDS 12 o'clock high!"

Pilot, "Oh, Shit, we're headed for a cluster flock....."
by Scully, you're not alone January 25, 2010
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When multiple dickheads flock into a certain, place, fandom or hobby, transforming it into a clusterfuck of assholery. They will then anally rape it until it is sore, rotten and a genuinely bad place for everyone.
Joe: Did you see what the SJW invasion did to Marvel Comics?
Rex: Yeah. Once they began cluster-flock to it, it was only a matter of time.
via giphy
by Blarg-chicka-honk-honk March 12, 2018
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