From Liquipedia StarCraft Brood War Wiki
Small Ground Unit
The Broodling is a small Zerg unit spawned when a Queen casts Spawn Broodling on a target. Two Broodlings spawn per spell cast. Upon their creation, they have a fixed amount of "energy" that represents their life span. Similar to Hallucinations, when this energy depletes, the Broodling automatically dies.
Spawn Broodling affects all ground units with the exception of:
Other important notes about Broodlings:
- Broodling energy is not affected by either Feedback or EMP Shockwave.
- Spawn Broodling fails if the Queen dies prior to the projectile connecting with its target.
- No Broodlings are spawned if the projectile hits a Hallucinated unit. However, the Hallucination is destroyed
The Broodling is relatively uncommon in professional play due to the costs of producing Queens and time necessary to accumulate sufficient Energy. Furthermore, the limited units that can be targeted can dissuade the Zerg player from using the spell.
Because Hive evolution is very rare in this match-up, the Queen is almost never seen in Zerg vs. Zerg. Therefore, Broodlings are never seen in ZvZ as well.
The most common target for Spawn Broodling in Zerg vs. Terran is the Siege Tank. It is usually optimal if the player targets Siege Tanks in a cluster as the Broodling's presence will cause other Tanks to shoot them thus damaging adjacent units through friendly Splash Damage.
Tanks may be targeted in the late game against a Terran Mech build, although the Zerg player will often opt for the more versatile Dark Swarm with Ultralisks and Zerglings instead.
Broodlings are rarely seen in Zerg vs. Protoss since the most expensive and potent Protoss ground units (Reavers, Archons, and Dark Archons) are immune to the spell. However, Spawn Broodlings can be used to snipe High Templars.