Credited to ColensoBBDO, their agency on record, and brought to life (or un-life) by The Dept. of Motion Graphics Hell Pizza's 2008 Happy Helloween promotional video created such a wicked backlash that it was censored off the face of the internet after virtually only 24 hours when it was released.

Now, a year later, is it still offensive or simply a product of pop culture gone awry? You decide.
http://www.strangekidsclub.blogspot.com/ (less info)