mushroom
verb [ I ]
informal uk/ˈmʌʃruːm/ usto increase in number or develop very quickly:
Low-cost airlines have mushroomed in recent years.
mushroom into sth The walkout mushroomed into a large-scale battle.
mushroom from sth to sth Area budgets mushroomed from $3.7 billion in 2005 to more than $6.3 billion this fiscal year.