Smilers are a race of androids that appear in the British sci-fi series, Doctor Who, primarily in the episode "The Beast Below".
Smilers are displayed within booths and have three distinct faces that convey their state of being - when smiling they are pleased and will not attack, when they show a look of displeasure they are warning people and when they show a face of pure rage they will launch an attack.
Smilers worked for their creator Hawthorne and installed fear in the population of Starship UK by feeding any citizen who broke the law to the Star Whale that acted as the vessel's support - they were also known to attack citizens who were merely deemed "no longer useful".
Smilers did not feed children to the Star Whale however, instead they sentenced minors to work at the Tower Of London - although they tended to stay within their booths when necessary they could leave the booths and become free-roaming.
The population was terrified of these machines and for good reason as they could effortlessly repair themselves form a great deal of damage, such as being shot.
In an alternate dimension in which the Doctor's adventures existed as a fictional TV show called Doctor Who, a fan dressed as a Smiler was present at a Doctor Who convention which the Eleventh Doctor visited with Ally in 2013.
The Winders are the police force of Starship UK. They are cyborgs: half-human and half-Smiler. Just like Smilers, their heads would rotate to reveal the malevolent expressions, with a lighter skin tone, whiter teeth, flat nose and brighter eyes. They would speak through their natural vocal cords when they were using their human faces, but talked through a speaker box when their Smiler face was in use. Most of the time they wore dark hoods to hide their Smiler features and acted like normal humans, keeping watch on the population. They were bound by oath to protect the system of Starship UK.