The no-holds-barred feud between cherubic pop star Justin Bieber and Black Keys drummer Patrick Carney has now gone into overdrive. The whole fracas got started when Mr. Carney, 32, said that Mr. Bieber, 18, shouldn't complain that he didn't get any Grammy nominations, because, well, he didn't deserve any.

"He's rich, right?" Mr. Carney said. "Grammys are for, like, music, not money. And he's making a lot of money. He should be happy."

But Mr. Bieber was not happy at all and tilted into Death Star mode, tweeting back that the Black Keys drummer "should be slapped around haha."

Haha? Haha? Did Mr. Bieber dare say haha? Not so fast, riposted Mr. Carney, who changed his Twitter alias to Justin Bieber, replacing his own photo with one vaguely resembling his newfound enemy. Then, tossing fuel onto the flame with a brilliant parody of Mr. Bieber's trademark tweeting style, Mr. Carney tweeted, "Gurl, you give me inspiration to make my music and toothbrushes and all thatz swag to u baby."

While Mr. Carney was waging this shocking, unprecedented scorched-earth campaign against the babyfaced pop star, Mr. Bieber's fans got into the act, unleashing all the naked, primordial savagery that social media can bring to bear on one's enemy. Typical was this contemptuous tweet directed at Mr. Carney: