What are, famously...
Ebon, sienna
High, low
Within, without, ubiquitous
Distant, close
Absent, present
Swift and slippery, not to be trusted
The mysterious things in question are
Heffalumps and Woozles, from Disney's version of Winnie-the-Pooh.
More precisely,
They're black, they're brown, they're up, they're down
They're in, they're out, they're all about
They're far, they're near, they're gone, they're here
They're quick and slick, they're insincere
Beware, beware
Be a very wary bear
Incidentally, "famously" is overstating it, at least so far as my state of knowledge goes. I had never encountered
the song in question (being unfamiliar with Disney-Pooh) but noticed the brown/down and near/here rhymes and went a-googling (first guesses: nursery rhyme, Dr Seuss, of course no luck with either; but putting in "black brown up down far near there here lyrics" did the trick.)
Sorry I didn't watch that movie and I know it has been answered but a rough answer could be
Rock mountains
Because
Ebon sienna
Their colour
High low
Their height
Within without ubiquitous
Rocks are almost every where on the earth inside and outside
Distant close
Many meanings . It might be distance.
Absent present.
In some area they are present and other not
Swift slippery
Swift can be there slope and slippery sure they are
Not to be trusted
Accidents happen on mountains