4chan Party Van
From The LURKMORE Wiki
First seen in a MSPaint comic, Anonymous answers his door after the person knocking claims it's the "4chan Party Van", but unfortunately it turns out to be the FBI, who proceed to exclaim "LOL J/K" and beat up Anonymous.
4chan Party Van is now used as a euphemism for "FBI", often posted during child pornography floods; became extremely popular after the "Jake J. Brahm" incident, where /b/ became aware actual FBI agents might be monitoring their chaos. This newfound knowledge both excites and terrifies many /b/tards.
