indelible ink (noun)

1. The killer left behind a trail of terror and used indelible ink to write his gruesome messages on the walls.

2. In the anime series, the main character possesses a pen with indelible ink that allows him to bring his drawings to life.

3. The superhero used a special pen filled with indelible ink to leave his signature mark on every page of his comic book.

4. The ancient sorcerer cast a spell using indelible ink, ensuring that his enchantment could never be undone or reversed.