It can be done with volumetric decals. Create a material parameter collection and add a vector parameter for the location of each blob. Add one, or many, scalar parameters to control their radius. In a volumetric decal material, create a spherical distance field for each blob.
find the smoothmin of all the blobs and feed the result to opacity mask.
Here, the vector parameters are set based on the world location(divided by the scale of the volumetric decal) of 10 invisible spheres that varying forces are applied to.
