happen
/ˈha-pən/
verb
to occur by chance —often used with it
to come into being or occur as an event, process, or result
to do, encounter, or attain something by or as if by chance
idiom
to come to or by a place by chance
He was about to leave when his old girlfriend happened by.
phrasal verb
to enter (a place) by chance
She happened into the room just as the music started.