Terraria (Wiki): Tome of Infinite Wisdom

This magic weapon specializes against single or multiple enemies, although the latter function proves superior. The Tome of Infinite Wisdom's first attack fires four non-piercing, high-velocity book pages. The second attack casts a Tornado, dealing 175% of the weapon's base damage, lasting for 4s or when stopped by a tall wall.   When using the Tome of Infinite Wisdom, the second attack is perfect against large waves of enemies or even bosses. It also works great for gathering Seeds, Mushrooms, or even the evasive Life Fruit.