Arnem land creek demon

The Northern territory´s underwater fiend.
Six metres-one tonne of prehistoric ferocity!
Hiding in the murky stream at the bend.
Where the locals go swimming and fishing.
The wet season´s lurking flesh-eater.
One day a young man slips under
with not so much as a splash.
The pale green demon one week in wait
sprung in a flash.
His friends scanned the surface
of the swimming hole.
To no avail- while the youth under the current
 died in a brutal deathroll.
A monster owned that part of the river
for more than a mile.
Living in the skin of a salt water crocadile.