Hey,
Not that this may be the method they used but maybe it’s real footage. Thick paint either on a sheet of glass held in front of the camera so you get the nice drip down or top view splat down for a nice contained one, Then they cut it up and use all of them as they see fit. Other approuch would be using water simulation software using blobs to make everything look like gunk. But I would shoot it, using a luma-key setup.
Hope that helps, I do the same for photoshop work, when we need paint dripples I go outside and have a paint setup and get white paper and black paint and go to town. Scan them in, I have a whole stack of lovley paint brushes now … and vector cuts. HUZZAH! 😛
..::hunz..