Hi Doug,
basically it’s just two copies of a square solid (100x100px) with a ramp filter.
Set the ‘Ramp Shape’ to ‘radial ramp’,
and the ‘start of ramp’ set to the middle of the solid (50,50 in this case)
You could also make a radial black to white gradient in Photoshop.
so you’ve got two (or more) copies, set their modes to multiply (the comp-background should be white) and animate them.
that gives you something like this:

I added an adjustment layer with a brightness-contrast-filter.
I often use brightness-contrast with a very high contrast (93-98%), that way it gives you a softer kind of anti-aliased threshold-effect.

So only the grey values that are dark enough show through, because of the multiply, when the two circles get nearer, the pixels in between get darker too, so when they reach the threshold, a connection between the two is visible.
here’s another variation using blurred text and a radial gradient.


I’ve included the project file for the blobby text: blobtext.aep
it just took a few minutes to tweak the blur-level, brightness-contrast setting and opacity of the layers.