Startling

startling
    adj 1: so remarkably different or sudden as to cause momentary
           shock or alarm; "Sydney's startling new Opera House";
           "startling news"; "startling earthquake shocks"
    

Startle \Star"tle\ (st[aum]r"t'l), v. i. [imp. & p. p.
   {Startled} (st[aum]r"t'ld); p. pr. & vb. n. {Startling}
   (st[aum]r"tl[i^]ng).] [Freq. of start.]
   To move suddenly, or be excited, on feeling alarm; to start.
   [1913 Webster]

         Why shrinks the soul
         Back on herself, and startles at destruction?
                                                  --Addison.
   [1913 Webster]
    

58 Moby Thesaurus words for "startling":
      abrupt, alarming, amazing, astonishing, astounding, awesome, awing,
      breathtaking, chilling, confounding, daunting, deterrent,
      deterring, disconcerting, discouraging, disheartening, dismaying,
      disquieting, disturbing, electrifying, eye-opening, fear-inspiring,
      fearful, fearsome, frightening, frightful, hasty, headlong,
      impetuous, impulsive, jarring, jolting, mind-boggling,
      nerve-shattering, overawing, overwhelming, precipitant,
      precipitate, precipitous, quick, scaring, scary, shocking,
      spectacular, speedy, staggering, stunning, sudden, surprising,
      swift, terrifying, unanticipated, unexpected, unforeseen,
      unlooked-for, unpredicted, unsettling, upsetting