let x_speed = rand(-3, 3);
let y_speed = 0;
let gravity_strength = 0.02;

while(!Obj_BeDeleted(balloon)){
  let old_x = Obj_GetX(balloon);
  let old_y = Obj_GetY(balloon);
  let new_x = old_x + x_speed;
  let new_y = old_y + y_speed;
  let new_angle = atan2(new_y-old_y, new_x-old_x);

  Obj_SetPosition(balloon, new_x, new_y);
  Obj_SetAngle(balloon, new_angle);

  if(/*balloon hits floor*/){ y_speed *= -1; }
  y_speed += gravity_strength;

  yield;
}