I wish I could have came up with the idea for this myself, but I got the initial setup from here: I spent some time pulling apart the .hip file, figuring out all the VOPs stuff, but I eventually understood it (it actually wasn't that complicated). It blows me away how smart some people are.
The wet map came from a Peter Quint tutorial. I did have to figure out how to get the motion blur working myself, so I was happy with how that turned out.
I have some ideas on how to improve the look of the noise. The crazy thing is that there's no particle sim at all on this, it's all in a VOP SOP.
I tried building particles to create little splashes when he hits the shadow, but this effect is dependent on point numbers, so adding more points complicated things. I'm going to take another crack at that when I have some time. All and all I was pretty happy with how it turned out, and I learned a lot.