Star Cell

Star Cells belong to the Stardust Pillar, which only exists after the Lunatic Cultist falls and the Lunar Events start. They spawn inside the pillar's area and drift toward you at a lazy pace, then pick up speed the moment you turn and run. Backing away does not shake them off, but moving away from the pillar itself does cut how many new ones appear.

Killing a cell does not remove it from the fight. It bursts into a cluster of Mini Star Cells, and any mini left alone long enough swells back into a full one that can split again. How many minis you get depends on how crowded the area already is, so your first kill scatters more than your tenth. Minis do not count toward the pillar's shield while they are small, but they do once they have grown back, and that detail is what makes the cycle worth exploiting.

The shield comes down after a set number of kills, and these enemies manufacture their own replacements for free. Leaving the minis alive and letting them mature gives you a renewable supply of things that count, plus banner progress you would otherwise have to grind out. The safe version is to seal the grown cells outside a small room and hit them through the wall with a weapon that ignores blocks, so the counter keeps climbing while nothing can reach you.

They arrive in clumps, so reach and spread beat single target damage. The Solar Eruption can wipe a cell and the entire litter it just produced in one swing. Vampire Knives heal off every body in the pile at once. The Flairon and Aerial Bane both clean up the small ones on their own, and the Inferno Fork, Nebula Arcanum, Celebration and Last Prism all cover enough space that the numbers stop mattering. Life Drain is the odd pick that works, since it latches onto every cell in range and raises your regeneration while it drains them.

The bestiary describes them as single-celled organisms multiplying on celestial energy, and the Stardust Cell Staff tooltip about cultivating an infection reads as though the pillar is growing them deliberately. Real cells divide by themselves and both halves live on. These only divide when something kills them.