The helium-voiced Quasimoto (his voice sped up in the studio to produce the effect) is an alter ego of the astonishing hip-hop producer Madlib. It sounds like the kind of gimmick that would last for ...

In the world of English-language hip-hop, some rappers use nicknames. But one Los Angeles musician creates entire alter egos. Rapper and producer Otis Jackson, Jr., has recorded under the names Madlib ...