Answer: mushrooming

AnswerCrossword Clue
mushrooming(of the smoke, fire, or flames produced by an explosion) Spread into the air in a shape resembling that of a mushroom
mushroomingrapid growth
mushroomingIncrease, spread, or develop rapidly
mushrooming(of a person) Gather mushrooms
mushrooming(of a bullet) Expand and flatten on reaching its target