if (one_chance_in(8) && !mons_is_shapeshifter(mon)

            if (one_chance_in(8)
                && !mons_is_ghost_demon(mon->type)
                && !mons_is_shapeshifter(mon)

static bool _valid_morph( monsters *monster, int new_mclass )

static bool _valid_morph(monsters *monster, int new_mclass)

    if (mons_class_holiness( new_mclass ) != mons_holiness( monster )
        || mons_class_flag( new_mclass, M_UNIQUE)       // no uniques
        || mons_class_flag( new_mclass, M_NO_EXP_GAIN ) // not helpless
        || new_mclass == mons_species( monster->type )  // must be different

    if (mons_class_holiness(new_mclass) != mons_holiness(monster)
        || mons_class_flag(new_mclass, M_UNIQUE)      // no uniques
        || mons_class_flag(new_mclass, M_NO_EXP_GAIN) // not helpless
        || new_mclass == mons_species(monster->type)  // must be different

        // These shouldn't happen anyways (demons unaffected + holiness check),
        // but if we ever do have polydemon, these will be needed:
        || new_mclass == MONS_PLAYER_GHOST
        || new_mclass == MONS_PANDEMONIUM_DEMON

        // These require manual setting of the ghost demon struct to
        // indicate their characteristics, which we currently aren't
        // smart enough to handle.
        || mons_is_ghost_demon(new_mclass)

void monsters::uglything_mutate()
{
    simple_monster_message(this, " mutates!");
    ghost->init_ugly_thing(type == MONS_VERY_UGLY_THING, true);
    uglything_init();
}

        return visible_to(targ);

        return (visible_to(targ));

        return mons_near(this);

        return (mons_near(this));

    return mon_see_grid(targ->pos());

    return (mon_see_grid(targ->pos()));

    // Special case: Polymorphing a (very) ugly thing will mutate it
    // into a different (very) ugly thing.
    if (type == MONS_UGLY_THING || type == MONS_VERY_UGLY_THING)
    {
        uglything_mutate();
        return (true);
    }

    void init_ugly_thing(bool very_ugly);

    void init_ugly_thing(bool very_ugly, bool mutate = false);

static unsigned char _ugly_thing_random_colour()

static unsigned char _ugly_thing_random_colour(unsigned char not_colour)

    return (colours[random2(sizeof(colours) / sizeof(*colours))]);

    unsigned char colour;
    do
        colour = (colours[random2(sizeof(colours) / sizeof(*colours))]);
    while (colour == not_colour);
    return (colour);

void ghost_demon::init_ugly_thing(bool very_ugly)

void ghost_demon::init_ugly_thing(bool very_ugly, bool mutate)

    // An ugly thing always gets a low-intensity colour.
    colour = _ugly_thing_random_colour();

    // An ugly thing always gets a low-intensity colour.  If we're
    // mutating it, it always gets a different colour from what it had
    // before.
    colour = _ugly_thing_random_colour(mutate ? colour : BLACK);

    void uglything_mutate();