Evolver

Evolver is a gun introduced in A Farewell to Arms. The gun evolves with every 5 unique enemy types the player kills. This changes its appearance, modifies its stats, and refills its ammo. The six evolutions, in order, are: amoeba, sponge, flatworm, snail, frog, and dragon.
 * The amoeba fires round projectiles that deal 6 damage.
 * The sponge fires sponge-shaped projectiles that deal 8.5 damage.
 * The flatworm fires round projectiles that deal 11.5 damage.
 * The snail fires a spread of three spiked snail shells that deal 11.5 damage each.
 * The frog emits a red tongue which latches onto the nearest enemy, similar to the Abyssal Tentacle.
 * The dragon fires blue flame projectiles which starts off slow and accelerates, dealing 37.5 damage. In this stage, the Evolver's maximum ammo drops to 150.

Like Gunderfury, the gun evolves even if it isn't being used.

Trivia

 * The flavor text "Tamagunchi" is a reference to the digital pets Tamagotchi.
 * The gun's description is a reference to real life evolution denial. In this phenomenon, some groups of people deny the existence of evolution for its supposed lack of concrete evidence.
 * The synergy is a reference to the metaphor that the mitochondria are the powerhouse of the cell. More specifically, the phrase, "the mitochondria is the powerhouse of the cell" was a meme for some time, owing in part to it being used in a viral image criticizing the educational quality of the school system; this is also thematically similar to the anti-intellectual stance of denial described within its entry.

Bugs

 * If the Evolver is dropped and picked back up in dragon form, the gun will hover much further away from the gungeoneer while held, and the gungeoneer's hand will appear to be detached from their body.
 * If the evolver is in its 6th stage and duct taped to another gun, dropping it and picking it back up may cause it to devolve