Can anybody clue me in to the wacky green lightning in ROTK?

I know its not out just yet, but the trailers have me puzzled- during many scenes which sem to be immediately before some tremendous battles with Sauron’s forces, there is this great pillar of what looks like green lightning/goo above the army. What is this? I’ve read the book, and don’t really recall Sauron’s armies being lead by a giant pillar of gooey green lightning.

Lemme Guess- Its the ark of the covenant! So THAT’s where the Nazis got the idea! :wink:

A pillar of smoke by day gooey green lightning by night…

Could be part of the alarm signal when Frodo and Sam start mixing things up around Cirith Ungol, or else the signal from Barad Dur to start fightin’.