You don't say

[Tyrn]

Hi,

What's the subj in Spanish? Like in the Urban Dictionary:

Used to express sarcasm when someone states the obvious, or states a fact that has been delivered like a second ago

Fat man: Dude, I think I have become fat
Dude:You don't say

I'm not sure that either no me dices or no me digas apply.

[Rusty]

¡No me digas!