This is an adjective (that's why it's hyphenated). To SPIKE means to take something to its highest point, to its limit. This adjective describes something that makes your adrenaline spike, such as a parachute dive: "Skydiving was an indescribable experience: the first ten adrenaline-spiking seconds after the jump from the plane, followed by the serene weightlessness of the free fall have to be experienced at least once in one's lifetime."

Thank you)