Swarm of Wrath

 — Magic weapon, which you can buy from Genoshi the Keeper. It fires blue shining petals, which can hit through several enemies. Despite the fact that you can attack only horizontally to the left or right, this weapon has a large damage radius due to writhing projectiles.

Can be upgraded to Eye Of Belial.

Trivia

 * This weapon, as well as upgraded version, is a reference to Chicken Invaders franchise.