Step aside, Fatboy - there's a new dance king in town, and he's named after a famous fictional whale. The small, shaven-headed American is the biggest thing on the floor right now, and he can thank a bunch of dead blues singers for his success. It was a rare archive of early blues songs which inspired his 2.5 million-selling album, Play, but it was the thrill of 21st-century techno which brought 4,500 punters down to a tent in Cork to see the diminutive dude when he headlined the Heineken Green Energy Festival.

Fatboy Slim can play records, but Moby, a wiry ball of Christian vegan adrenalin, bounds onstage with a band and DJ in tow, then pulls a bunch of rabbits out of his techno hat. He sings, he plays guitar, he bangs a syndrum, he wallops a set of bongos, he even strums the bossa nova on an acoustic guitar, and shouts "Thank you! Thank you! Thank you!" like a seasoned showman. Anyone who attended Moby's Dublin show earlier this year would know exactly what to expect: a hop, skip and quantum leap through hardbag techno, hardball rock 'n' roll, and hard-up blues samples. The latter dominated the mood, providing the historical spur for Run On, Honey and Why Does My Heart Feel So Bad? In this affluent, agnostic age, it's weird to hear a tentful of teens and twenty-somethings singing the lines "Oh lordy, trouble so hard/ Don't nobody know my troubles with God" from Moby's biggest hit, Natural Blues.

Moby dipped into his own archives, resurrecting his rave anthem, Feelin' So Real, and sending the crowd into transports of - oh, go on, say it - ecstasy. For his finale, however, Moby stood astride his keyboard like a visiting alien, and announced "the fastest song ever made". As the b.p.m. (beats per microsecond) rose to heart-stopping levels, you could almost picture those poor old bluesmen spinning in their graves.