BMW are running an ad for their 2 Series Coupé with this slogan:
Bites as bad as it barks
A certain fifteen-year-old, Albert Gifford, who is making something of a name for himself for taking large companies to task for their grammar, wrote a series of emails to BMW, reprinted in The Daily Mail, complaining that bad wasn't an adverb, and 'so cannot be used in this context'. But is he right?