How dangerous was a triceratops?

Triceratops probably was an herbivore, so it would probably not attack an animal unless it was provoked. However, if provoked, they weighed 6.5 to 13 tons and had three horns capable of impaling a human. In fact, fossil evidence shows us a case where a Triceratops fended off a T-Rex with its horns. So, in short, they wouldn't hunt you down, but if you gave them good reason, they could kill a human with ease.