Top 10 Most Terrifying Creatures to Ever Livebr br Fearsome animals existed at the time of the dinosaurs that you, hardly, know about. Fortunately, they have gone extinct millions of years ago!br br Here are some prehistoric creatures that fit the list of top 10 most terrifying creatures of all times.br br 10. Liopeleurodonbr 9. Quetzalcoatlusbr 8. Sarcosuchusbr 7. Thalattoarchonbr 6. Dunkleosteus br 5. Titanoboabr 4. Megalodonbr 3. Tyrannosaurus rexbr 2. Predator X (Pliosaurus funkei)br 1.