Used commonly as a remark of surprise to a nonsensical statement by youtuber Jacksfilms in his popular "Your Grammar Sucks" series, it has leaked out of the internets and into the real world. It was originally a failed attempt at typing "What the fuck" by youtuber alpen000, and when appearing in Jack's YGS series (episode 21), Jack reads the comment as it is supposedly pronounced, saying it with a heavy foreign accent of his own creation. Jack's way, the only correct way, of pronouncing ":a what a fucke?!" is as follows: "A-whah-da-foook?", making sure to rise in pitch as the expression progresses. Note that the phrase has four syllables, but occasionally, Jack will repeat the da and make the phrase have 5 syllables. It is applicable in real life to any situation where one may say "what the fuck" or in any other bizarre situation.
Toby Turner: Jack! Your girlfriend says she's tired of being made fun of, and is breaking up with you!
Jack Douglas: :a what a fucke?!