pigs can / might fly

/pˈɪɡz kan mˌaɪt flˈaɪ/

/pˈɪɡz kæn mˌaɪt flˈaɪ/

used to express one's disbelief about something happening or being true

Examples

1. The day I get arrested is the day that pigs can fly.

2. "And pigs can fly!"

3. He always says this, that pigs can fly if shot out of a large enough cannon.