The dust is made of the page
Each block breaks into particles sampled from its own pixels, so the ash coming off a result block is blue where the title was and grey where the description sat. It drifts up and to the right, thins out, and by the time you notice the block is gone it has been gone for a second already.
Blocks do not all go at once either. They stagger, which is what makes it read as an event rather than a page reload.
Half, then half again
One snap takes roughly fifty percent of what is still standing. Snap again and it halves what survived. Six snaps fills the gauntlet and empties the frame. There is an undo, and almost nobody presses it, which is a shame because the reassembly is the better half of the animation.
It was real for a few weeks
In 2019 the gauntlet appeared in actual results for a film tie-in. Clicking it dusted half the listings and halved the result count. Then the promotion ended, which is why google thanos snap and thanos snap google still get typed in by people expecting something to happen.
Tie-ins always expire. Grogu google lasted a season. What survives is what people rebuild, which is also the story of zerg rush.