The Broodlisk is an artificially evolved strain of Broodling.
From the beginning of the first Koprulu Wars, the Zerg's ability to spawn Broodlings was one of the most feared weapons in their arsenal. Once a biological unit gets infected by the spores, Broodlings would burst out of the hosts instantly killing them. While the first part of this tactic is effective in taking out an enemy unit quickly, the two units created leaved must to be desired. They were weak in attacks and had a very limited lifespan.
Through the use of Xel'Naga gene splicing data, Broodlings can be altered into a more useful bio-weapon. After augmenting the Zerg's assimilation abilities, this new strain gains one of two new forms when they attack/infest an infantry unit of either Terran or Protoss origin (Aliens: Xenomorph).
When the Overmind perished, a certain being continued its research into to hybridizing the Terrans. The overall results were basically the same as the Overmind's at the beginning. Finding no help in any of that data, the Vaul worked to improve the deadliness of the Infested Terran. The primary problem with the first versions of the Infested Terrans was that enemy units could shoot them down before triggering the near nuclear level explosion.
To solve this, the Broodlisk in Terran-form has an armor-like carapace similar to the ones used by Hydralisks. While not as sturdy, they can take a moderate amount of damage before exploding. To augment their offensive capabilities, they evolved "natural" flamethrowers on both arms. Fueled by the explosive fluids within them, Terran-Forms can spray flames from up to 100m.
Zerg infestors and Terran research teams have tried to combine Protoss and Zerg DNA in countless experiments. Through many failures, some subjects with potential were finally created and hidden in multiple secret labs across the galaxy. DNA blueprints for some of the more resilient strains were integrated into the Broodlisk resulting in the Protoss-Form.
The main weapon of this Form consists of two bone-like spikes protruding in both palms (Buffy the Vampire Slayer: Adam). Each spike can impale any enemy unit no matter what type of armor they have. While the Protoss-Form has more health than the Terran-Form, it still has a finite lifespan like the Broodlings that made it. To ward off cellular degeneration, the spikes are segmented and can lengthen with a muscular tentacle similar to Shuriken Colonies and drain the life force/psi energy of any biological unit impaled (Marvel: Omega Red). Each enemy drained dry gives the Protoss-Form a few minutes of life, so it is always hungry for enemy infantry.
- Terran-Form - has heavy carapace, flamethrower attack, and retains ability to self-destruct
- Protoss-Form - limited lifespan. Needs to constantly feed off biological units to gain 50 energy