send shivers down someone's spine
panic
worrit
make someone's blood run cold
trouble
gnaw
hairy
worry someone sick
spook
disquiet
crap oneself
put the fear of God into
scarecrow
anxious
shuddersome
nail biter
worry
skittishness
restiveness
worryingly
hair-raising
white-knuckle
put the cat among the pigeons
anxiousness
horrify
afraid
anxietize
terror
uneasiness
bugbear
hobgoblin
piggle
frighten
horror
horrid
alarming
overnervousness
geek out
buttock-clenching
anxiety
take fright
apprehend
funk
nail-biting
begruntle
out of one's skin
worriment
make someone's hair stand on end
have kittens
quake in one's boots