a combination of two unfortunate or negative circumstances or events
from Li'l Abner cartoon strip
“The double whammy of those two set me on a course of thinking about issues I had never done before,” Sherwood told the Times.
Why new cuts will be a double whammy for Bentonville—and anyone with a mutual fund.
This “double whammy” of predation and competition enables jellyfish to cripple a food chain by essentially nibbling at its ankles.
A two-part or two-pronged difficulty; a dual disadvantage: the double-whammy of steep home prices and steeper interest rates (1940s+)