A meme involving giant, disfigured heads resembling those of Touhou characters. It originated on 2ch in early 2008 when an Anon tried to make a Shift_JIS portrait of Reimu and Marisa and failed horribly. Another Anon thought the failed attempt was humorous and drew the infamous original picture (shown below right). Ever since that fateful day, yukkuri heads have dominated parts of NicoNico and made cameos in numerous other pieces of Touhou fanart. Their catchphrase "Yukkuri shiteitte ne!" literally means "Do it slowly!", but has been more loosely translated as "Take it easy!" by the English-speaking Touhou community. This remains the basis for many of the jokes centered on yukkuris.
by That one guy over there in the August 7, 2009