What's the noun for surprise? Here's the word you're looking for.
surprisal
(obsolete, military) A surprise attack or ambush; a sudden or unexpected assault. [16th-19th c.]
(obsolete) A sudden coming-upon someone or something unexpectedly or unawares. [17th c.]
(obsolete) A surprising event or occurrence. [17th-19th c.]
(obsolete) The feeling caused by being surprised; surprise, shock, amazement. [17th-19th c.]
An information measure first defined by Myron Tribus in his 1961 book Thermostatics and Thermodynamics (D. Van Nostrand, New York) so that it is equal in bits to the base-2 log of 1 over the probability, with the result that e.g. the number of choices equals 2 to the number of bits.
“The images of the electric eel and the popping tangle of seaweed convey something of the speed and surprisingness of William's mind.”
“They have the complexity and the surprisingness of human beings, and human beings are capable of anything.”
“We can also estimate the surprisingness of applicability conjectures, by assessing how likely it is that a production rule step would produce very few models.”