Wiktionary
went pear-shaped
vb. (en-simple past of: go pear-shaped)
Usage examples of "went pear-shaped".
And Siobhan had projected gloomily that if things went pear-shaped--if civilization fell apart despite the shield's protection--the hibernacula would most likely serve the starving survivors as cellars of thawing meat.
If this insertion went pear-shaped, as it probably would, then he could very well be on the run by morning.