Manipulator arm
From Tardis Wiki, the free Doctor Who reference
The manipulator arm is the large mechanical arm usually found on most Dalek models, the exeptions being some Dalek Emperors' models and the Special Weapons Dalek-type model.
Abilities
The manipulator arm is generally shaped like a plunger, however the black tip at the end (which gives it its "plunger" shape) can change into different shapes for when needed and has enough suction to kill a Human, whether for offensive perposes or for extracting information from brainwaves. (DW: Dalek)