Hidden Runner is the dinosaurian term for the genus Troodon.
The animal's only appearance, so far, has been in the TV series episode, The Spooky Nighttime Adventure, where it is represented by a green and blue individual voiced by Rob Paulsen. He has the ability to blend in with his habitat due to his multi-colored markings, giving the impression that he can turn invisible.
Hidden Runner was thought to eat meat, hence why he was feared. However, as he doesn't appear to be a Sharptooth, it seems more likely that he is herbivore or omnivore. Actual Troodon were omnivorous.
- Actual Troodon had teeth, but Hidden Runner doesn't have any.
- Though the character Hidden Runner was thought to be a deadly carnivore by the characters, he doesn't appear hostile, which is realistic as Troodon was omnivorous.