A Double Shah is one who lures you to invest money in a ponzi \ pyramid scheme with an unflinching promise of unusually high return on investment.
A Double Shah takes your money on the pretext of doubling or in some cases tripling your money before handing it down to you. A Double Shah promises abnormally high returns and may produce people from your neighborhood, acquaintances, workplace to enamor you into thinking that investment in the 'scheme' is a viable option.
Raj: Nay, you should more like a double shah. I won't make the same mistake twice.