Nebula Floater

It belongs to the Nebula Pillar's own spawn set during the Lunar Events, so it exists only after the Lunatic Cultist is dead and only inside that pillar's area. Three can be alive at once, which does not sound like many until all three are shooting.

It grows a small orbit of eyes and the eyes do the firing. That has a direct consequence: the longer one lives the more lasers come out of it per second, so a fresh floater is far less dangerous than one you have been ignoring. Kill them promptly or watch the volume climb.

It also wants a clean line to you. Given one, it hovers at range and shoots. Deny it one and it stops shooting and comes for you instead, straight through terrain, so a wall buys you contact damage rather than safety.

It relocates on a timer and can also blink the instant you damage it, so a steady stream of small hits feels wasted. Single heavy hits land better. The teleport is also the real threat, because it can drop one nearly on top of you, and sprinting blind around the pillar is how people lose a chunk of health to something they never saw arrive. It keeps a small buffer and even accounts for where you are heading, but the buffer is not generous.

Circling is the cleanest dodge. The lasers are aimed rather than tracking, so a constant orbit puts you off every line as it is drawn. Where that breaks down is volume, and floaters are never the only thing in the pillar. Bring something with crowd coverage. If the Vortex Pillar is already down, a Vortex Beater with Chlorophyte Bullets handles the whole spawn list. The lasers leave visible trails, which is how you find floaters you have not spotted yet, though those trails are easy to mistake for the energy streams that dead enemies send back toward the pillar.