When it comes to popularity, most musicians are reluctant to risk losing it. Gaining mainstream popularity as a musician is such a ludicrously difficult accomplishment that once they've got it, they're desperate to hold on to it. But popularity doesn't come without its disadvantages. In many ways, mainstream success cements the public's (and more importantly, the fans') opinions and expectations. Many musicians achieve popularity because of a certain sound or style, and to experiment with these ingredients can often lead to disaster (take Metallica's Load, for example, which saw many fans disappointed). This inability to experiment can lead to disillusionment and frustration and that's where alter egos come in. Alter egos are a safe way for musicians to distance themselves from their main act and try new things. If it goes badly, they can just retreat back to their primary stage name. The general public isn't bewildered and musicians can safely experiment everybody wins. For this reason there are a ton of amazing musical alter egos out there, failed attempts at gaining a new kind of popularity and artists whose secondary projects were decent but simply never took off.