ludum-dare-42/objects/obj_enemy_generator/Alarm_0.gml

var rand = random_range(0,50);

if ( rand < 50) {
    for (var i = 0; i < 10; i++) {
        instance_create( random_range(5, 475), -20,obj_enemy_popcorn);
    }
}
alarm[0] = 60 + (rand ^ 1.5) //easier enemies at lower end of scale