Of all things!

of all things

Of all the possibilities (this is the most surprising or unlikely). When he retired, he took up painting, of all things. He had never even picked up a paintbrush before that! After spending his childhood in and out of detention centers, he became, of all things, a cop.
See also: all, of, thing
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

Of all things!

Can you imagine?; Imagine that! (Usually said about something very strange.) She wore jeans to the dance. Of all things! Billy, stop eating the houseplant! Of all things!
See also: all, of
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
See also: