If you think this snake is big...
... Then quickly get acquainted with the new (or old?) champ, Titanoboa:
Left: A model vertebra of an extant anaconda, arguably the largest snake in the world. Right: The fossilised vertebra of Titanoboa. WTF!
Dramatic name. Dramatic find. Let's just put it this way: this snake would eat the motherf**king plane. See Ed Young's or PZ Myers' accounts for more information.