The works of J.R.R. Tolkien have yet to be fully adapted for the big screen, and even though Peter Jackson's films delivered a few dozen hours of material from Tolkien's stories lots of great content and characters haven't made it into the movies.
Some of the biggest and baddest villains in Tolkien's lore, such as Morgoth, the first Dark Lord, or Ungoliant, mother of all giant spiders in Middle Earth, were featured in The Silmarillion, a posthumous collection put together by Christopher Tolkien that many see as the prequel to The Hobbit and The Lord Of The Rings.
Morgoth will definitely make his way onto the big screen if an adaptation of The Silmarillion is ever made, and when he does we may get to see his dragon Ancalagon the Black in action.
Ancalagon was so large and fearsome it was said he could "blot out the sun from miles away", and when he died his fallen body was responsible for destroying a volcanic mountain range, which led to the destruction of the northwestern portion of Middle-Earth.
Something tells me that sequence will be done in CGI...