What it "looks" like is interesting. A black hole is invisible by definition, since the escape velocity is greater than the speed of light. The black hole will become visible through two mechanisms:
The "Einstein ring". The powerful gravitational field of a black hole bends light coming near the event horizon, so anyone looking in the direction of a black hole will see a strange "ring" of distortion as the light from distant stars (or the Sun, depending on your relative position) passes around the volume black hole occupies. You might see something like this:
This is actually going to be very difficult to see in the scenario, since the black hole being created is of such a small diameter that the Einstein ring will also be similarly microscopic in size. If you are seeing an Einstein ring the size of the illustrations you are probably far too close to the black hole already
The other thing which makes black holes visible is the accretion disk of in falling matter. In this case you won't see anything because the micro black hole will be starting in relatively clean space without much matter to ingest until it hits the solar atmosphere. The tiny size of the black hole will also limit the actual amount of matter being ingested, so any accretion disc forming as it passes through the solar photosphere will be much too small to notice.
Now the question Is there a way to create a bomb to destroy a star? suggests that there might be another effect. If the in falling black hole can create enough energy deposited in a small volume of the star, it might trigger a chain reaction of fusion in the outer layers of the Sun, creating what is in effect, an artificial type 1 nova.
If that is the case, you will see the CrushSun fire the weapon, followed shortly afterwards by a blinding flare as the star is induced to go nova. After that excitement dies down, the remains of the star will settle for a very long time until the black hole in the centre grows enough to start consuming mass at an appreciable rate (probably centuries). The extra gravitational pull in the centre will cause the star to continue to brighten as heavier elements are pulled towards the core and reach conditions that induce fusion, as well as the energy of the accretion disc forming in the centre of the star itself. The eventual demise of the star will probably be announced as the accretion disc pokes through the surface of the star and stellar material is rapidly flung into space.