monkey wrench
snag
booby trap
pitfall
throw a spanner in the works
throw a wrench in
sticky wicket
spanner
let
shit
trouble
ravel
puzzler
hit a snag
bind
stumbling block
thing
fix
duck's guts
gotcha
crux
problem
stymie
dilemmalike
stumblingblock
predicament
bugbear
mare's nest
situation
scrambling
goof-up
praemunire
kicker
troublement
mountain
dilemma
give someone a hard time
box
bewilderment
out of one's element
brainteaser
in a pickle
booger
snarl
oops
up a gum tree
quandary
rub
plight
duh factor
escape fire
tough cookie
barrier
devil
roadblock
trip
sin
soup
put out a fire
hitch
workaround
stumper
swamp
bear
bitch
entangle
at a pinch
in a pinch
tsuris
more than one bargained for
mishap
anyone's guess
confuzzle
sitch
pain point
between a rock and a hard place
hard nut to crack
tough nut to crack
half-measure
kick at the can
picture
mire
roll of the dice
hit
pinch
pisser
pull a rabbit out of a hat
hang-up
banjax
where the shoe pinches
unsimpable
wall