How on earth did they create Elizabeth's tears?

Reference to desired effect: https://youtu.be/Ro7agnfOqqw?t=28s

I have recently began using "Shader Forge", which by the way is an amazing tool, to create some cool (yet rather basic) shaders and materials. I followed some of their beginner tutorials and the one that I found particularly interesting was the one were we got to create a dissolving shader/material: https://youtu.be/qCkdVX1RhJ4?t=9m50s

When I revisited one of my favorite and inspiring games, namely Bioshock Infinite, I noticed that the tears that Elizabeth create (the girl in the first video if you havn't played) probably are made using some similar effect to the dissolving material. The difference beeing that their "noise" being a perfect circle and that it is somehow "floating" in and out by some small parameters (as seen in the first clip)

My current setup is really similar to the one in the tutorial, with some minor trials and errors (mostly failed attempts) to creating this effect... My question is then, of course, how was this effect created, and is there a way to replicate it in Unity 5? I would really like to know since this really is a astonishing cool effect :3

Thank you in advance for taking your time.