The Cremator is an enemy cut from Half-Life 2, and is regarded as a favorite both by fans, and Half-Life 2's developers. A jar containing its severed head can be seen in Eli's lab. When the player approaches it, Eli will remark, "We're still not sure what that does, Alyx brings in the strangest things."
It was to partially be assembled in factories by workers, their heads seen being placed on a conveyor belt in an assembly line by Child Workers in one of City 17's industrial districts.
Their purpose was to clean the streets of City 17, incinerate bodies, and to kill any Xen wildlife that may have stowed away in train cars en route to the city. It used a large weapon known as the immolator, which, functionality-wise, was a laser/plasma flamethrower with medium range with a hose connecting it to the Cremator's exposed stomach.
Despite having no AI in the leak, an npc_cremator entity is still present in the leak's .fgd file, with adjustable parameters for immolator range, burn duration, reload duration, and arc scale. Currently, no modders have re-implemented any of these functions.
In addition to the .fgd entry, CLASS_CREMATOR exists in the leak's source code, and many NPC classes have their affiliation with CLASS_CREMATOR set to fear. The retail's source sdk code includes DMG_PLASMA, which has a comment indicating that it was supposed to be used by the cremator's weapon, and the damagetype includes a non-functional feature that disintegrates corpses if they take enough plasma damage.
The famous LeakNet patch for the Leak adds npc_cremator as a functioning entity, but the NPC is currently incomplete as it lacks the ability to attack.