I really want to do this kind of effect where it looks like a person is disintegrating away, but I have no idea what it is called:
THanks To Bala's clue in the comment.... I found the original source photo....
It's merely Adobe Photoshop's Oil Paint Filter
Here's one with these settings:
This is a completely new image generated by running the oil paint filter on the same source photo. This is not merely a reposting of your sample image.