BOGGLED

Either literally or figuratively to stop or hesitate as if suddenly seeing a bogle.

"The dogs went on, but the horse boggled at the sudden appearance of the strange beast."

To be bewildered, dumbfounded, or confused.

"He boggled at the surprising news."

To confuse or mystify; overwhelm.

"The oddities of quantum mechanics can boggle the minds of students and experienced physicists alike."