Suction arm

The suction arm, also known as the sucker arm, sucker-stick, (TV: The Power of the Daleks) sucker-rod, (PROSE: Doctor Who in an Exciting Adventure with the Daleks) or simply the sucker, was the most common type of manipulator arm used by the Daleks, sporting the eponymous circular suction cup at the end. (PROSE: Prisoner of the Daleks)

Even if the Dalek died, its arm could still operate machinery for a live person. (TV: Remembrance of the Daleks) The arm also had a telescopic feature to extend its length. (TV: The Dalek Invasion of Earth, Dalek)

The suction arm was inadvertently inspired by the recently regenerated Fourteenth Doctor. After crashing into the Creation of the Daleks, the Doctor accidentally smashed the multi-dextrous claw off of the prototype Dalek that Davros and Castavillian were working on. The Doctor replaced it with a sink plunger from the TARDIS which Castavillian stuck on the Dalek in place of the claw. Upon seeing the makeshift arm, Davros decided that he liked it. (TV: )

Behind the scenes

 * The suction arm was notably the very first part of a Dalek to appear on-screen, as seen attached to the Dalek which confronts Barbara Wright within the Dalek City at the very end of their first episode, "The Dead Planet". The Daleks would only be revealed in full in their second episode, "The Survivors".
 * In the online video game, The Last Dalek, the player can use the "Metaltron's" extending suction arm as a close-quarter weapon.