Event Horizon

The Event Horizon is a craftable post-Moon Lord spell tome that is the direct upgrade to the Relic of Ruin. It fires a ring of stars around the player that orbit their location at the time it was used, and home in on nearby enemies. If no enemies are nearby, the stars expand outwards, go back inwards again and finally drift off. Upon contact with enemies, they transform into lingering black holes with half damage and infinite piercing, rapidly dealing damage while stationary before dissipating after 1 second.

Trivia

 * The event horizon is the area around a black hole where gravity becomes so strong that it is impossible for any matter or energy to escape, including light. This is referenced in the item's tooltip.
 * The weapon is a reference to the spell card, Black Magic "Event Horizon", used by the character Marisa Kirisame from the Touhou Project series.