Disciple of Bolas | Magic: The Gathering
Formats Disciple of Bolas is Legal in
Official Oracle Text for Disciple of Bolas
Official Rulings for Disciple of Bolas
7/1/2012 : You can't sacrifice more than one creature this way.
7/1/2012 : The ability is mandatory. If you control at least one other creature when the ability resolves, you must sacrifice one. If you don't control any other creatures at that time, the ability won't do anything.
7/1/2012 : The creature's power when it was last on the battlefield is the amount of life you gain and the number of cards you draw.