if (con == 0)
{
    with (obj_mainchara)
    {
        if (place_meeting(x, y, obj_triggervolume))
            other.con++;
    }
}
if (con == 1)
{
    instance_create(x, y, obj_caterpillarchara_susiebreakspots);
    con++;
}
if (con == 2 && !instance_exists(obj_caterpillarchara_susiebreakspots))
    con = 0;