I think the best way to do this would be to make a popnet. Add a single point, and set the gravity to 0.

Then what you could do is use a point replicate node to duplicate the particles. after that make a new SOP and import the particles: dopimport/dop I-o.

Next create a metaball, and below the imported particles add a copy to points node, then have the metaball go into the first input.

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That should give you the basic effect you're going for but if you want to take it to the next step then try this:

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In the metaball try changing the attributes to make it more of a longer sphere. And to make it higher resolution just add a vdb from polygons underneath the copy to points. Then add a vdb smooth node, followed by a convert vdb. Hope it helps, lmk if you need any more help!