A Splicer is simply a Rapture citizen who has repeatedly "spliced" themselves with Adam. While the substance may provide a host of physical enhancements, it also takes a toll on the mind. Houdini Splicers are crazed humans that now possess the ability to teleport at will and launch fireballs from their fingertips.

There are five research levels that can be attained by snapping photos of Houdini Splicers:

• Research Level 1: Increased Damage (+)
• Research Level 2: Natural Camouflage
• Research Level 3: Increased Damage (++)
• Research Level 4: Easier to see where Houdini Splicers will re-appear.
• Research Level 5: Increased Damage (+++)