Mystery photo 2: the answer

Here is the photo I took on the Grand Union Canal a few days ago in full.


And here it is with a bit of tweaking.


Looks better like that, doesn't it?

And here's another one.


Fascinating, isn't it?

But what is it? Well, it's not fancy artwork on a boat, nor, as far as I know, a Vermicious Knid (an Adamsism, Simon?).

It's foam emerging from an outflow onto the canal about half way between Buckby Top Lock and Norton Junction. I regret now not taking a wider shot putting it into context, but I was taken by the amazing shapes the foam took. Neil, in his comment, suggests it's foam onto which oil has been dropped. Foam, yes, but there's no visible oil, unless the foam picked some up just as it came out onto the canal. Ally, commenting anonymously, also says it's foam, but Neil, you were there first. Captain Ahab, sorry, not this time!