take fright
To become very frightened or startled (by something). Often followed by "at (something)." Investors began pulling their funds from the company, having taken fright at the allegations against its CEO. As the thunder cracked overhead, the horse took fright and threw its rider to the ground.
take ˈfright (at something)
(written) be frightened by something: The horse took fright and galloped off as the car passed.