From Longman Dictionary of Contemporary Englishwildfirewild‧fire /ˈwaɪldfaɪə $ -faɪr/ noun [countable, uncountable] especially American English a fire that moves quickly and cannot be controlled → spread like wildfire at spread1(2)
Examples from the Corpus
wildfire• Another wildfire movement was liberation theology, expressed in Base Ecclesiastical Communities.• It arrived in our town by word of mouth and crackled like wildfire through the grapevine of gab and gossip.• The giggling spread like wildfire, and eventually forced the closing of some schools.• Word of it spread like wildfire among geophysicists.• The slander spread like wildfire and was only checked when the drunk who invented it confessed in a magistrates court.• It was the sort of story that would spread like wildfire.• That wildfire feeling might have got a hold a month back, but it would not be allowed to do so again.• Late Monday, the wildfire was still out of control. 