BioShock/Enemies

Splicers
In the world of BioShock, Splicers are humans who have injected themselves with the genetic modification agent known as ADAM so frequently that it has warped them, sending them into spiralling insanity. They constantly talk to themselves about lives half-forgotten, family and friends long dead, and rivalries no longer relevant in any manner. They are addicted to ADAM, and are the main character's primary foe.

Splicers are split into groups-each named for its abilities. Leadheads and Thuggish Splicers are the most common, compared to the more powerful, faster, and smarter Spider Splicers and Houdinis.

Lesser Splicers
Thuggish Splicers are the most common variety of Splicer, usually carrying pipes or wrenches similar to the main character's. They are the weakest enemy in the game and usually do not have many items.

Leadhead Splicers use guns, as their names would suggest. They are somewhat stronger than Thuggish Splicers. In the early levels, pistol Leadheads are the most common, while machine gun Leadheads take over later. There is a variant that uses grenades called the Nitro Splicers. Leadhead Splicers usually carry ammunition for their gun, EVE hypos, health kits, or money.

Greater Splicers
Spider Splicers are primarily female, faster, stronger, smarter, and altogether vicious versions of the Thuggish Splicers capable of climbing walls with the use of large hooks. They attack with the hooks from close range or with darts from afar. With the right research, their organs can be used like health kits.

Houdini Splicers are the most powerful variety of Splicer in the game. Capable of turning invisible, teleporting, throwing fire and ice, and much more resistant to the main character's Plasmids. They appear mostly late in the game.