intrude, irrupt -- (enter uninvited; "They intruded on our dinner party"; "She irrupted into our sitting room")
erupt, irrupt, flare up, flare, break open, burst out -- (erupt or intensify suddenly; "Unrest erupted in the country"; "Tempers flared at the meeting"; "The crowd irrupted into a burst of patriotism")
explode, irrupt -- (increase rapidly and in an uncontrolled manner; "The population of India is exploding"; "The island's rodent population irrupted")