jolt, shake, rattle, agitate, paralyze, startle, sicken, panic, threaten, transfix, shock, unnerve, alarm, intimidate, scare, terrify, horrify, daunt, disgust, frighten, distress, petrify, revolt, nauseate, make one's skin crawl, spook, appall, strike fear into, make one's hair stand on end, send chills down one's spine, scare the bejesus out of, scare the pants off of, make one's blood run cold, frighten someone out of their wits, scare the shit out of, scare shitless
recoil, choke, scatter, crouch, shake, snap, twitch, freeze, falter, quiver, knock down/over, jump, scream, quaver, charge, hide, bolt, start, stampede, panic, shy away, cower, tremble, shrink, transfix, blanch, pale, weaken, drain, wobble, take cover, flee, shout, gag, teeter, barrel, stop (in one's tracks), gasp, yell (for help), cry out, run (off/away), pitch (forward from one's hips), dive (for cover), hightail it, cringe, flinch, come undone, hyperventilate, vibrate, shiver, shudder, wince, go numb, back away/off/up, turn back/away, shit one's pants, wet oneself, twinge, quake, grimace, go to pieces, shake in one's boots, break into a sweat, dry up/out
grasp, clutch, squeeze, beat, pound, worry, crouch, bother, sweat, perspire, rise, mount, hide, dart, pant, secrete, stalk, menace, threaten, watch, wait, cower, grow, darken, cast a shadow, flare, intensify, pulse, lie (low/in wait), endanger, risk, imperil, hazard, jeopardize, suspend, trouble, alarm, intimidate, burgeon, heighten, degenerate, worsen, fear, dread, alert, lay low, guard, fret, throb, aggravate, exacerbate, warn, caution, loom, haunt, portend, tick, creep, bear down on, live in fear of, watch out/for, beware