Okay... here goes.

Walls ooze shadows, darkness flows
all around does slink your foe
shifting, sliding all around
anywhere he could be found
rattling chains that hold no bind
battle of the peculiar kind
fell it once your foe gets stronger
a battle which runs even longer
foe goes lurking without sight
fell twice, and you'll end this fight.

this was made on the spot because a friend knew the answer to my old riddle -_-'

And we can't have that can we?