Terraria (Wiki): Magnet Sphere

The Magnet Sphere is a magic weapon that summons a glowing cyan sphere from the player’s cursor. The sphere travels in a straight line, bouncing off solid blocks (desktop, mobile, console) and having a reduced movement in liquids. As it moves, the sphere will zap the nearest enemy. After traveling for more than 15s (desktop, mobile, console) / 11s (3DS, old-gen consoles) or having gone 52 tiles, the cyan sphere will disappear. Attempting to use the Magnet Sphere will create a new cyan sphere, and the existing one will fade away.   Before combat, the ideal modifier is Mythical, as it increases the Magnet Sphere’s stats.    The Magnet Sphere comes shining when clearing a room full of enemies. Albeit lacking the capability to damage a certain radius, its rapid-fire mode makes fair compensation. The Magnet Sphere can also detect and damage certain enemies like disguised Mimics.