Acid pellet

Prowl brought urine to a gunfight. No wonder Scavenger wasted him.

Acid pellets are small projectiles formed of acid. The Autobot Prowl uses a gun that is capable of firing acid pellets, as well as lasers. Scattershot wields an automatic acid pellet gun, which is also used by Computron. A burst from Scattershot or Computron will burn you. Up to 500 times per minute. Doubleheader's Pretender shell, not as much with its semi-automatic acid pellet pistol. In some continuities, Warpath uses a similar weapon but on a larger scale; Acid shells.

Fiction

The Transformers cartoon

After Sparkplug Witwicky's metallic Frankenstein creation Autobot X unsurprisingly ran amok, Prowl, Ironhide and Trailbreaker stood up to the crazed robot with Prowl using his acid pellets to incapacitate Autobot X. Autobot Spike Responding to an SOS when the super-computer called TORQ III ran amok, the Autobots discovered TORQ was capable of controlling other machines in the area and Prowl found himself being swallowed whole by a rogue mechanical scoop. He fired an acid pellet down its gullet to give it the worst case of indegestion it's ever had and corroding its inner workings. Day of the Machines Later, Prowl would use his acid pellets to disarm a group of time displaced wild west outlaws by melting their guns. Dinobot Island, Part 2

Marvel Comics continuity

Marvel The Transformers comics

During a confrontation between the Terrorcons and the Technobots in the Nebulan city of Splendora, Computron blasted Abominus with his acid-pellet gun while berating the Decepticon for being too dim-witted to understand what was happening. Love and Steel!

Transformers Annual 1985

Due to being published early in the franchise, "Hunted!" is out of continuity with the above.

Investigating suspicious activity in South America, the Autobots Prowl, Bumblebee, Twin Twist, and Top Spin discovered a replica of Megatron's fortress on Cybertron. Attacking the Decepticons, Bumblebee and the others found themselves suddenly paralysed by Dirge's fear-inducing engines but thankfully Prowl managed to steel his logic circuits and shot Dirge down with a few acid pellets. Hunted!

Regeneration One

On a Cybertron overrun with shadow-leeches, Kup found Scattershot's acid pellet gun outside the Star Chamber and used it to pierce through the door, much to the consternation of Ultra Magnus. The War to End All Wars, Part 5

Notes

• In a nod to his Generation 1 namesake, Transmetal 2 Prowl's packaging bio notes that he fires acid pellets, although it doesn't say from where.