Spawn Broodling

What happens when Enemy Summoner meets Chest Burster? A villain that has the ability not only to kill a character but also to generate allies.

This is distinguishable from The Virus in that the Spawn Brooder is not spreading itself, and from Face Full of Alien Wingwong in that it is an ability that takes a much shorter amount of time and is generally not considered that sort of attack. See also Flunky Boss, who might use this as an attack, Baleful Polymorph, and The Punishment.

Quick and painful examples

 * Emperor: Battle for Dune has Tleilaxu Leeches, which would spit a parasite onto enemy tanks that would eventually destroy them, creating another Leech. They also had a zombie-like enemy called a Contaminator that would spawn another Contaminator every time they killed an infantry unit.
 * Starcraft: Queens and their Broodlings; the Zerg Queen has an ability called "Spawn Broodling" that kills an enemy unit and creates two Broodlings, similar to Zerglings except in how they are made.
 * Similarly, Brood Lords in Star Craft 2 "create" Broodlings using their attacks, but that's because they are flinging them into battle.
 * Dungeons and Dragons has three Epic Spells: Animus Blast, Animus Blizzard and Demise Unseen.
 * One of the early Looking for Group strips has Richard summoning the skeletons of some enemy soldiers... while the soldiers are still alive.
 * Warhammer 40000 has the Gift of Chaos/Boon of Mutation (essentially the same ability, but one is Chaos Marine psychic power and the other is a Daemon shooting attack), which attempts to turn the target into a Chaos Spawn (a mindless mass of mutated flesh). The Orks also have a special character that can polymorph an enemy into a Squig. The Tyranids have a special character that can infect units arriving from the reserve, causing them to turn into Ripper Swarms.
 * Warhammer Fantasy Battle also has a necromancy spell that tears the souls out of the victims and turns them into Spirit Hosts, aswell as a spell availeable to the Daemons that turns enemies into more Daemons.
 * Chryssalids from X-COM: UFO Enemy Unknown.
 * Tentaculats from the sequel, Terror From the Deep. Now they can fly.
 * In Shin Megami Tensei: Devil Survivor, Belzeboul, AKA Beelzebub, can implant his fly eggs in you, which hatch a turn later, and join in.
 * The Magic: The Gathering expansion Rise of the Eldrazi includes a card called "Corpsehatch" that is virtually identical in function to the Trope Namer ability; it kills a creature and creates two Eldrazi Spawn in its place.
 * There's also Skeletonize, which burns away a creature's flesh and (assuming three damage will kill it) leaves behind and undead skeleton under your command.
 * Undead Knights The entire point of the gameplay is to attack enemy knights and turn them into zombies. You can even work it into your combos to zombiefy them instantly after weakening them.
 * A double-blast of the TMD in Singularity turns an enemy soldier into a ghoul-like monster that hunts by sound. It will usually attack other enemies because they don't know not to be quiet. A third blast to the monster will turn it into an Action Bomb.

Slow and painful examples

 * Dungeons and Dragons: Anything with Spawn, Implant, or Create Attacks; for example, the Slaad and the Marrash.
 * Special mention goes to Extract Water Elemental.
 * Extra special mention goes to the Vargouille.
 * Alien vs. Predator: Xenomorphs of the genetically engineered variety.
 * Warcraft 3 has a few abilities like this (Doom, Parasite, Dark Arrow...), but they create a unit upon death instead of insta-killing.
 * Warhammer Fantasy features the sword of change, a magic blade that can mutate its victims into masses of random Body Horror under partial control of the user. There's also a Skaven spell that changes it's victims into a unit of Clanrats.
 * World of Warcraft has Curse of Doom, essentially the same spell as Doom from Warcraft 3, except it doesn't insta-kill the target, but instead deals large amounts of damage. Should this damage kill the target, it spawns a demon. Death Knights also have a talent that may count: Bloodworms, which causes their melee swings to have a chance of causing worms to burst out of the target and attack it.
 * Guild Wars has a spell (Malign Intervention) that reduces healing, and creates a minion if the target dies while affected.
 * If your GM is cooperative, cast Animate Dead on a carnivorous creature's last meal and see what happens. If all works out, they'll have a zombie in their tummy.
 * Particularly horrific version in Dragon Age Origins in the form of the Broodmothers. Lets just say that female grey wardens have an even bigger reason for seeking out a quick death on the battlefield than their male counterparts and leave it at that.
 * In Alien Swarm, the parasite enemies will latch onto a player, and the infestation is not cured in time, will exit the host, along with several parasite buddies.
 * A Real Life example is the Spider Wasp which hunts down spiders and paralyzes them rather than killing them, then they lay a single egg in their prey and bury them. When the egg hatches the young will feed on their host till they're mature enough to grow out.