throw a wrench in
go to the trouble
hard
megachallenge
underchallenge
bid
torfer
tough nut to crack
enodation
run for one's money
step to
hard nut to crack
at a pinch
make hard work of
in a pinch
take up
lightning in a bottle
defy
doo-doo
boil the ocean
dare
chase
put a hurt on
wing and prayer
queer someone's pitch
square one's shoulders
enmesh
pull off
unmess
nodus
upseek
make an effort
line of attack
square the circle
challengingly
gantlet
pain point
get out
gauntlet
addressable
hard-set
draw a line in the sand
take the bull by the horns
copout
hard put