if (mons_is_submerged(mon) && !mon->can_drown())
        return (false);

    if (!mons_is_submerged(mon))
        return (true);
    const dungeon_feature_type feat = grd(mon->pos());

    return (true);

    // Monsters can only drown in lava or water, so monsters that are
    // "submerged" in other features (air elementals in air, trapdoor
    // spiders in the floor) are exempt from this check.
    if (feat < DNGN_LAVA || feat > DNGN_WATER_STUCK)
        return (false);
        
    return (mon->can_drown());