burst into

to start crying suddenly

to start laughing suddenly

to start singing suddenly and enthusiastically

to suddenly catch fire

to start clapping suddenly to show approval

to enter a room suddenly, often with force or excitement

to start crying noisily

often used as 'burst into peals of laughter'

to have a sudden, uncontrolled expression of an emotion, often used as 'burst into a fit of laughter/rage'