Like the other enemies you can take research photos to gain rewards & bonuses against certain enemy types. You first meet the Houdini Splicers in the level Arcadia glens, they are the enemies that teleport around the place throwing incinerate fire balls at you. There are plenty of them on this level and is thus very possible to complete the research on them before leaving this level! So keep taking those snappy snaps ensuring you are close enough for decent detail, the subject is in the centre of the shot & you are getting your bonuses for action shots & multiple subjects (although the Houdini’s are usually on their own).