Spike LauncherWeapon 6
Source Pathfinder Guns & Gears
Damage 1d8 Piercing
Type Martial
Range 120 feet
Price 250 gp
Weight 2 bulk
Built from the spiked tail of a manticore, a spike launcher is designed to launch large, spear-like projectiles. A spike launcher is a +1 striking weapon. It's a distinct type of martial firearm that deals 1d8 piercing damage. It has the backstabber, fatal aim d12, and kickback traits with a range increment of 120 feet and reload 2. It uses the critical specialization of the bow weapon group, rather than the firearm critical specialization.
Activate 
Interact (evocation, magical)
Frequency once per day
Requirements The spike launcher is loaded
Effect The spike launcher fires a volley of smaller spikes in a 10-foot burst centered anywhere within its range. Make a Strike with the spike launcher against each creature in the area. On a success, the spike causes the creature to take a -5-foot status penalty to their Speed. On a critical success, the creature becomes Immobilized instead. In either case, the creature, or an adjacent creature, can use an Interact action to remove the spike and end the penalty or immobilized condition.
Craft Requirements The initial raw materials must include the tail of a manticore.
Traits
Something of uncommon rarity requires special training or comes from a particular culture or part of the world. Some character choices give access to uncommon options, and the GM can choose to allow access for anyone. Less is known about uncommon creatures than common creatures. They typically can't be summoned. The DC of Recall Knowledge checks related to these creature is increased by 2.
BackstabberWhen you hit a flat-footed creature, this weapon deals 1 precision damage in addition to its normal damage. The precision damage increases to 2 if the weapon is a +3 weapon.
FatalAimIt's possible to hold the stock of this weapon under one arm so you can fire it with a single hand as long as the other hand isn't holding a weapon, shield, or anything else you would need to move and position, to ensure the weapon doesn't slip out from under your arm. However, if you use both hands, the weapon can make fatal attacks. When you wield the weapon in two hands, it gains the fatal trait with the listed damage die. Holding the weapon underarm stably enough to fire is significantly more complicated than just releasing one hand from the weapon, so to switch between the two grips, you must do so with an Interact action rather than Releasing or as part of reloading.
KickbackA kickback weapon is extra powerful and difficult to use due to its high recoil. A kickback weapon deals 1 additional damage with all attacks. Firing a kickback weapon gives a -2 circumstance penalty to the attack roll, but characters with 14 or more Strength ignore the penalty. Attaching a kickback weapon to a deployed bipod, tripod, or other stabilizer can lower or negate this penalty.