adj.excited by sudden surprise or alarm and making a quick involuntary movement

"students startled by the teacher's quiet return"; "the sudden fluttering of the startled pigeons"; "her startled expression"

The startled seahorse: is the hippocampus necessary for contextual fear conditioning?
Topologists startled by new results.
Ghostly spacecraft returns from dead to haunt its startled owners
Part D Plans May Be Startled By Drug Costs for Dual Eligibles
Startled Pests Face Makers of Ultrasonic Control Units
Changes in pulse, breathing, and steadiness under conditions of startledness and excited expectancy.
Escape manoeuvres of schooling Clupea harengus
Stopped visual motion
Sonic collar sheep protector
Functional Evidence for Visuospatial Coding in the Mauthner Neuron