Splicer

"This little fish looks like he just had his cherry popped. I wonder if he's still got some ADAM on him."

- Splicers looking on Jack, searching for ADAM in his body

Splicers are the main enemies within the BioShock series. The remains of Rapture's human population, they are the result of the violent conflict during the Rapture Civil War. During this war and the chaotic days that followed, the splicers apparently murdered most of the sane population of the city. Due to abusive ADAM consumption, their bodies and minds have been deformed beyond repair (though some of their physical deformities can be attributed to Dr. Steinman's plastic surgery), and they have become dependent on the substance, both mentally and physically. Many of them still wear Masquerade Ball masks, perhaps, as Atlas suggested, out of shame at how ADAM has deformed their bodies.

BioShock
In BioShock splicers wander the corridors and the tunnels of Rapture, searching for ADAM, usually in the form of Little Sisters, which often puts them at odds with their Big Daddy protectors—something which Jack can easily exploit to help him survive. Splicers tend to wear very little armor (if any), but they have advanced physical strength and tend to be extremely aggressive in contrast to the calmer Big Daddies. They will sometimes work in groups, use Plasmids and sometimes even play dead to get the advantage on the player.

Thuggish Splicer
The Thuggish Splicer attacks with melee weapons. They can be found throughout the game and are fairly weak, but make up for it by running fast and attacking in groups whenever they can. Later on in the game this Splicer type upgrades, making it immune to the Electro Bolt Plasmid and Static Discharge Gene Tonic, so be prepared.

Leadhead Splicer
The Leadhead Splicer attacks with either a Pistol or a Machine Gun. They can also be found throughout the game, but are more dangerous than the Thuggish Splicer since they can attack from a distance and will almost always hurt a bit even if they are brought down easily. These will always keep their distance from the player whenever possible, but at very close range, they will attempt to pistol whip them. It is worth knowing that they have to reload their guns, just like Jack, and are defenseless when doing so. They also have more health than a Thuggish Splicer, making them harder to take down, especially if there are more than one.

Spider Splicer
The Spider Splicer is the first Splicer the player sees when they arrive in Rapture, although the player only starts fighting them in Neptune's Bounty. These Splicers can crawl on the ceiling and throw hooks at the player from afar, which can be caught and tossed back with Telekinesis. When on the ground, the Spider Splicer will get near enough to physically attack the player, then immediately jump onto the ceiling or backflip away and come at them from another angle. Their agility and ability to crawl on walls make them difficult to hit, and their modus operandi, which involves ambushing the player by crawling on the ceiling, can easily surprise anyone who is unprepared, however one can easily hear them moving on the ceiling.

Houdini Splicer
The Houdini Splicer is first encountered when the player enters Arcadia. These Splicers have the ability to turn invisible in the middle of combat. They can be tracked through smoke that appears around them whenever they disappear or reappear. This smoke becomes much more visible upon researching this Splicer to the fourth research level. The Houdini Splicer will most often attack by shooting balls of fire (and, in some cases, ice), but like the Leadhead Splicer, will attack physically when at close range. An easy way to track them is with Insect Swarm, which will follow the targeted Splicer even if (in the case of the Houdini) it is invisible. In combat, the Houdini Splicer uses a hit and run strategy by appearing, attacking with a fire or ice attack, and then vanishing to repeat the cycle.

Nitro Splicer
Nitro Splicers are found rarely throughout the game, mostly in Neptune's Bounty. The first one the player will encounter is in the Medical Pavilion. They will attack by throwing Grenades (and, later, Molotov cocktails) at the player from a distance. At melee range, they will either throw a smoke bomb to the ground, temporarily blinding the player, or they will attempt to flee, tossing an explosive over their shoulder or attempt to kick the player doing moderate damage. Upon dying, they will drop a live Grenade, with the intent of damaging the player if they were at close range. A common way of killing this Splicer type is by using Telekinesis to catch its grenades and throw them back at it. Researching this Splicer type will increase the chance that their explosives turn out to be duds.

BioShock 2
After ten years of splicing and surviving, splicers have become much more powerful than those who were encountered in the original game. They are far more deformed, with their faces often having conformed to the shape of their masks they often used to wear. Their limbs have heavily mutated, becoming lankier and, in some cases, the bone structure remodeling itself (such as the developing of extra fingers, toes, or even talons). However, the remaining splicers show a twisted form of unity, due to the influence of Sofia Lamb and the Rapture Family. The splicers loyal to the Family are no longer hostile to Little Sisters, but they see Subject Delta as an enemy and attack him on sight.

Some Splicer models seen in the first game are still present in BioShock 2, such as Leadhead Splicers and Spider Splicers, among other newer or evolved models, now unique to the second game. Splicers are also able to throw grenades while firing their weapons at Delta.

Brute Splicer
A new Splicer type which makes its first appearance in BioShock 2. The Brute Splicer is much bigger, more powerful and bulkier than any other Splicer, and is able to pick up an array of items or debris strewn around Rapture, such as large rocks, and explosives, and throw them at the player. Brute Splicers can also perform staggering jumps several meters in length and height, such as off of balconies, or onto walkways above the ground.

Splicer Models
There are ten Splicer models in BioShock and eight in BioShock 2. Their names are not revealed in-game; instead, they are associated with the sound files used for their sound bites in the game data. The Pigskin, Plastered Splicer, Rosebud, and Waders only appear in the first game. The models that return in BioShock 2 have a more deformed appearance. Additionally, two new splicer models were introduced with the Minerva's Den DLC for BioShock 2.

In All Games

 * Baby Jane
 * Breadwinner
 * Dr. Grossman
 * Ducky (Shares the same voice as Waders in BioShock 2)
 * Lady Smith
 * Toasty

BioShock Only

 * Pigskin
 * Plastered Splicer
 * Rosebud
 * Waders (Voice used for Ducky in BioShock 2)

BioShock 2 Only

 * Brute
 * Buttons (Minerva's Den DLC only)
 * Crawler
 * Heady (Minerva's Den DLC only)

Trivia

 * Early in the design process of BioShock, Splicers were known only as "Aggressors"
 * The term "Splicer" is a reference to gene splicing, a natural process that occurs during RNA transcription in cells.
 * Several splicer models are based on soldiers from the First World War who sustained horrific facial injuries and subsequently underwent pioneering surgery to reconstruct their faces.
 * There is a last Splicer model in BioShock 2 which was removed from the game and appears only in the "Hunting the Big Sister" video (see the gallery below). Concepts art for this model also appear in the Deco Devolution artbook. Despite the model having a full face, the concept implied that most of his face and teeth are missing. The only inclusion of this Splicer model in the game appears in the prologue cutscene, as one of the 1958 Splicers that surround young Eleanor, which Subject Delta steps on him by dropping from above a staircase. One distinct trait of this model is the right sleeve is marked with a broken "Great Chain" symbol.