function rotate_daily_nemesis() {
    // Un-feature current nemesis
    $old = new WP_Query([
        'post_type' => 'nemesis',
        'meta_key' => 'featured',
        'meta_value' => true,
        'posts_per_page' => 1
    ]);
    if ($old->have_posts()) {
        while ($old->have_posts()) {
            $old->the_post();
            update_field('featured', false, get_the_ID());
        }
        wp_reset_postdata();
    }

    // Pick a random one and feature it
    $new = new WP_Query([
        'post_type' => 'nemesis',
        'posts_per_page' => 1,
        'orderby' => 'rand'
    ]);
    if ($new->have_posts()) {
        while ($new->have_posts()) {
            $new->the_post();
            update_field('featured', true, get_the_ID());
        }
        wp_reset_postdata();
    }
}
add_action('nemesis_daily_event', 'rotate_daily_nemesis');

// Schedule event
if (!wp_next_scheduled('nemesis_daily_event')) {
    wp_schedule_event(time(), 'daily', 'nemesis_daily_event');
}