What is Did Ya??
1.
It simply asks the question, "Did you actually do that?", however, it drips with sarcastic disbelief or belittlement.
Alternates are "Do ya?" or "Will ya?"
Henry: "I've given up drinking."
Jimmy: "Did ya? I'll buy you a beer at Mulligan's and you can tell me all about it."
Horace: "I have an IQ of 133."
Jimmy: "Do ya? Then why is your shirt on backwards, stupid. Ha, you looked."
Headley: "When I die, I'm going to have my remains cremated and compressed into a diamond!"
Jimmy: "Will ya? It looks like the process has already started on your head, precious."
See