This pic was on my Aussie forum a while back. We weren't to sure if it was photoshopped, but coastal carpets can get to around 4m, sometimes larger, and get big enough to take on wallabies and small kangaroos.
We have large snakes here anyway. Scrub pythons (Amethystine Sp) and Olive pythons (Liasis Sp), can get between six and eight meters, and a photo (legit) went around a while back of an olive constricting than eating a maybe 4 meter crocodile!