to freeze (from fear, etc.), to be unable to move (e.g. from surprise)...

to shrug (shoulders), to duck (head), to draw back (body)

terrified, horrified

to cringe with fear, to cower with fright, to be terribly afraid

to cringe with fear, to cower with fright, to be terribly afraid

to be unable to move while seated (because of fear, surprise, etc.)

to be unable to move while seated (because of fear, surprise, etc.)...

channeled apple snail (Pomacea canaliculata), golden apple snail

to be petrified, to be unable to move, to be paralyzed (with horror)...

to pin the enemy down, to glare another down (and render impotent)

to freeze (from fear), to be unable to (too frightened to) run

to be unable to move while seated (because of fear, surprise, etc.)

to shrug one's shoulders

to hug tight, to grasp firmly, to embrace tightly

to duck one's head, to pull in one's head, to duck down...

three-way deadlock

three-way deadlock