Glass Dalek

A Glass Dalek was a Dalek variant created by Davros for the reproduction of his Imperial Daleks.

In Tranquil Repose on Necros, Davros used the Glass Daleks as part of his experimentation. By placing a cryogenicaly-frozen head into the casing, the head would mutate into the deadly creatures that make up the Imperial Daleks

When the head has become another Dalek, the Glass Dalek casing changes into that of an Imperial Dalek and another glass casing takes a new head.

Arthur Stengos almost became a Dalek before his daughter, Natasha, killed him.(DW: Revelation of the Daleks)