Terraria (Wiki): Blood Thorn

The Blood Thorn is a magic weapon that summons Blood Thorn projectiles with wall-penetrating capabilities.   When used, Blood Thorn projectiles have different ways of spawning.   By default, Blood Thorn projectiles appear from random solid blocks or platforms, circling the player’s cursor. When a solid block hinders the player’s line of sight and cursor, projectiles will instead appear from a circle around the obstruction point, facing the player’s cursor. If midair or no solid blocks, using the Blood Thorn will spawn its projectiles from the player’s hitboxes or a circle around the player respectively. However, projectiles will not appear from actuated blocks or background blocks.   The Blood Thorn is best modified with Mythical for a wide array of stats improvement.   In combat, the Blood Thorn is great for clearing a room full of enemies and holding off invasions.