Phoenix

 is a gun. Firing the gun creates a short-ranged cone that sets enemies on fire.

Trivia

 * This gun may be a reference to the Phoenix Blaster from the game Terraria.
 * The synergy is a reference to Phoenix Down from the Final Fantasy series.
 * Phoenix's sprite shape is the same as the Shellegun.

Bugs

 * The phoenix companion will still fire bullets with bullet modifiers (such as Katana Bullets, Angry Bullets, etc.) even if the items that give the effects have been dropped.