Forbidden Sun

The Forbidden Sun is a craftable Hardmode spell tome. Similarly to the Venusian Trident, it shoots out a fireball that, upon contact with either a tile or an enemy, creates an explosion of cream-colored particles. The explosion lingers for two seconds, dealing rapid damage to any enemy caught in its radius. The explosion can inflict damage to enemies behind tiles and can damage an unlimited amount of enemies. If the projectile hits less than 4 blocks away from liquid, the explosion will not occur. Both the projectile and the explosion inflict the On Fire! debuff to hit enemies.

Trivia

 * Its name may be a reference to the Dark Souls II fire spell of the same name, which has a similar explosive effect.