Just days after taking aim at Metallica and Black Sabbath, admitting he can't take their music seriously, the guitar great has turned on the late Jerry Garcia's rock act.

He tells Billboard, "The Grateful Dead is where everybody got it wrong. Just poodling about for hours and hours... Boring s**t, man. Sorry, Jerry."

In his recent New York Daily News interview, Richards said, "(Rock music) sounds like a dull thud to me. For most bands, getting the syncopation is beyond them. It's endless thudding away, with no bounce, no lift, no syncopation.

"Millions are in love with Metallica and Black Sabbath. I just thought they were great jokes."