The Firebat is an infantry support unit. Its main attack is a flamethrower that consists of two short parallel line splash of 8 concussive damage. This is further enhanced by a radial splash of 8 concussive damage near the end of the flame that damages units that were not hit by both line splash attacks. Generally, a unit can only take at most 16 concussive damage from a single Firebat attack, but attacking large units (such as a Siege Tank or an Ultralisk) from certain angles may land all three.
Researched at the Academy.
Stim Pack effects are not cumulative. A Firebat cannot be killed by means of a Stim Pack.
The Firebat is an effective unit in TvZ. In the early game, it excels in killing Zerglings. Many Terran players will place a Firebat and a Medic on their ramp to keep Zerglings from running through. A couple Firebats placed on your ramp shortly after you move out can hold off many Zerglings that may perform a backstab on your empty base. A Firebat can also be part of a Sparks Terran rush. The Firebat can take one more hit than Marines against Sunken Colonies. This is why builds such as Sparks Terran use firebats. However, as the game progresses, the Firebat loses its power. Firebats are not very effective against anything except Zerglings and to some extent Hydralisks. They do, however deal full damage under Dark Swarm, and occasionally Terrans will begin adding greater quantities of Firebats to their late-game armies to combat defilers. It is common practice to bring along a couple Firebat with your Marines and Medics to fight a Zerg's early game Zerglings. Because there are Marines alongside the Firebats, the Firebats usually get more Zergling kills than otherwise.
The Firebat excels at killing drones. Many Terrans will put Firebats along with their Medic Marine force into Dropships for their harass.
Firebats have very little application against Terran. Although Firebats are still good at killing workers, they have no advantage over Vultures in the early game. A Firebat can be made slightly sooner than a Vulture if an Academy is built instead of the first Factory. However, that Firebat will likely not do as much damage as a slightly later Vulture and you will be behind if they built a Factory. Firebats are not effective at any other time either. All other Terran combat units are ranged, making it easy to destroy the Firebat before the Firebat destroys its target. More importantly, Firebats do significantly reduced damage to the Mechanical units that are the mainstay of Terran vs. Terran matchups.
Firebats deal full damage to Protoss shields, and are questionably viable as a surprise early game attack in an Infantry based-build. However, standard TvP, which involves Factory units, is generally more effective. Occasionally, a Terran player will land a Barracks at a Protoss expansion and produce Firebats, with the intent of harassing the expansion.