The Fluctus' large projectile hitbox makes it a good mid-ranged crowd-control weapon especially when doing Archwing Interception and Defense missions as enemies come in in waves.
The Fluctus' projectiles also bypass the barriers protecting Shield Dargyns (and their Hellion counterparts) from front attacks, giving the weapon an edge over most Arch-guns when dealing with such threats.
This also allows players to safely defeat them from range instead of trying to go into melee, as getting into contact with their shields will cause Electricity damage that can become particularly fatal at higher levels.
The Fluctus (along with the Centaur and the Itzal) were accidentally leaked in Update 15.6.1, where a bundle called the "Itzal Raider Pack" visually replaced the Stealth Pack in the Market. The Stealth Bundle still functioned as normal however.
Curiously the bundle referred to the Fluctus as a crossbow.
Fluctus is a Latin word, which is most commonly translated to "waves".
The Fluctus fires horizontal projectiles, despite having a vertical shape.
The Fluctus is tied with the Cyngas for the second-highest per-shot damage among Arch-guns, after the Velocitus.
At release, elemental mods didn't work on the Fluctus. This was fixed as of Update 15.10.