In BioShock, the terrifying Little Sister wields an ADAM syringe to collect the substance — which can create strong stem cells. Regardless of what the syringe is used for, it’s scary. Many cosplayers have created the prop, and I recently saw Redditor N0_R0B0’s take on the syringe. He says:

I wanted to try something a little different with it. The back of the handle is slightly oversized because it’s housing two batteries. A triple A that runs a small air pump, and a 9 volt that runs LED lights in the bottle.
The switch on the side turns on the lights, and the red button switch pushes air through the aquarium filter in the bottle when the handle is squeezed. This gives a really neat looking bubbling effect to the liquid when the bottle is filled! This makes it look like it is actually doing something when it’s used.

Volpin Props made a replica of the ADAM syringe, too:

Get details on that build at their blog.

In yet another build, AWE me’s DIY Prop Shop tackled an ADAM syringe last fall: