happen

happen /ˈhæpən/ verb
happens; happened; happening
happen
/ˈhæpən/
verb
happens; happened; happening
Britannica Dictionary definition of HAPPEN
[no object]
1 
: to take place especially without being planned : occur
2 
not used in progressive tenses
a  : to do or be something by chance — followed by to + verb
b  — used with it to describe something that occurs by chance
c  — used to make an angry or forceful statement — followed by to + verb

happen along

[phrasal verb] US, literary + old-fashioned or happen by
: to come to or by a place by chance

happen into

[phrasal verb]
happen into (a place) US
: to enter (a place) by chance

happen on/upon

[phrasal verb]
happen on/upon (someone or something) literary + old-fashioned
: to find or meet (someone or something) by chance

happen to

[phrasal verb]
happen to (someone or something)
: to affect or involve (someone or something) as the result of an event or action
especially : to affect (someone or something) in a bad or harmful way