Flower of Fire

Flower of Fire is one of many unique Magic Items found throughout Terraria, and is a moderately rare drop from the Fire Imps which inhabit the Underworld. When cast, it launches a slow-moving fireball which arcs sharply downward, being affected strongly by gravity. The fireball will also ricochet off of solid objects up to five times, or until it hits an enemy, whichever happens first. The spell does reasonable damage and has some moderate knockback, considering the relatively low cost in Mana; it also works very well for hitting enemies behind objects or walls.

Trivia

 * This item is a reference to the Super Mario Brothers franchise, in which one of the 'power-ups' includes a flower (the "Fire Flower") that allows the player to throw fireballs which behave somewhat in the same manner.