Hidden Runner is a Troodon whose only appearance, so far, has been in the TV series episode, The Spooky Nighttime Adventure. He is a green and blue individual Hidden Runner 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.