What is Ta-na!?
1.
The negative of a "ta-da!" but with all the same self-impressed enthusiasm, for sleights of hand or mind which slyly accomplish nothing of the sort they seemed to at first -- i.e., a "ta-da!" combined with a "naaah."
From Reddit (7gwbw):
voltron013: From Hawaii you can see China.
7oby: but Japan is in the way?
GeoAtreides: No, Japan is hidden by earth's curvature, so he can see China. Ta-na!
See