Solar Fragment

The Solar Pillar fires these itself, straight up from its peak, and they arc back down under their own weight. That is the whole behavior, and it means the pillar is contributing to the fight rather than sitting there while its guards do the work. The pressure comes from overhead while everything else is happening at eye level.

One dies against the first solid thing it touches, so a floor of platforms a few blocks above your runway soaks up the entire barrage and you never see one land. If you did not build a roof, they count as enemies rather than projectiles, so any weapon swing destroys one on contact and a wide arc clears the sky without you changing what you were doing.

It shares a name with the crafting material the pillar drops, which is what most people mean by solar fragment. The two have nothing to do with each other. These fall out of the sky, hurt on contact, and leave nothing behind.