If you could go back in time and stop any one person or group's musical career, who or what would it be?
This isn't a "go back in time and assassinate" someone question. It's just their musical career never takes off and thus any music they ever would have made is no longer in this timeline.
On 3 April 1998, on the eve of a promotional tour for a new Milli Vanilli album, Back and in Attack, featuring Pilatus and Morvan on lead vocals, Pilatus was found dead from an alcohol and prescription drug overdose in a hotel room at Friedrichsdorf, near Frankfurt. His death was ruled accidental. The album has never been released.