I thought st. Elmo's fire was like spontaneous combustion..
as in a buddhist monk bursting into flames...

or like foxfire...the glowing swamp gas phenomenon
http://en.wikipedia.org/wiki/Foxfire_(bioluminescence)

more on will o the wisp here:
http://en.wikipedia.org/wiki/Will_o%27_the_wisp

i thought it was a type of bird...oh, yes, whipoorwill...