Answer:
(I'm guessing its the black plague)
It was frightening because it whipped out numbers of people within days. And you didn't know you had it until it was too late.
Explanation:
The plague was especially frightening to people in medieval Europe for these reasons:
It was highly contagious.
Infected people died quickly after the onset of the first symptoms.
It had painful symptoms.
I took an L and check the answer :p
