they just coalesced into a blob as they cooled due to the not-really-magic of surface tension

Why not tension ruling both processes, gravity trying to collect the initial material and later redistributing the part of impact weathered material that doesn’t escape Stein’s gravitation?

Btw, the initial material is AFAIU grains, once radiative melted or not, not molten larger bodies. Dunno if impact heating manages to melt the larger bodies, I thought it was the then higher radioactivity that did most of that assuming the body becomes large enough.

Also, IIRC impact processes tends to wear down topography in most cases. [Even if hardy grains can form caustics, i.e. sharp points and pillars, in an impact flow. Impact weathering preferentially from a set of smaller angles (due to the geometry of an extended body) will still make them eventually disconnect - fall off. So the process is emergent smoothening, for small impacts.] For example, sand blasting smooths.

Steins is AFAIU a rare asteroid, with spectra indicating that it comes from a larger body that had managed to melt and separate different materials. So perhaps it can be round (which I hear it likely is, from reflection studies) for several possible reasons. I would love to have an astronomer explain and sort out these processes.

Yes, it’s a very weak joke. But thank you for your question, which prevented me from making an even weaker bathroom joke about expelling asteroids.

I’ve read, somewhere, and heard on night talk shows, that an object (from Earth) can change an asteroid’s trajectory, without touching it. Is that concept what this is about?