A much more effective version of 'what the fuck?!', becuase people will tune in when the notice your new spin on the overused phrase.
This phrasial outburst can be used in the same exact context as 'what the fuck!?'.
man #1:I love mayonaise in my kool-aid.
man #2:What the Damn?!
man #3:Naw foo, it's all about the Miracle Whip.