1. Paralyzing with terror
   "The petrifying roar of the lion froze everyone in place"

1. Change into stone
   "the wood petrified with time";
   - lapidify
    
2. Cause to become stonelike, stiff or dazed and stunned from fright
   "The horror petrified his feelings"; "Fear petrified her thinking"
    
3. Make rigid and set into a conventional pattern
   "slogans petrify our thinking";
   - rigidify, ossify

See also: alarming

Type of: blunt, deaden, fossilise [Brit], fossilize, stiffen

Encyclopedia: Petrify