Robert Cop, a robotic policeman, is one of the characters of the fictitious Scary Go Round line of comic books, purportedly published as fiction in the Tackleford universe. (Mordawwa is another such character, who eventually took on a "real" existence in-universe as personified by Erin Winters, who had previously read the comic-book version of the character.) The multiple SGR comics in which Robert Cop purportedly appears are described in the ads and columns of Expecting To Fly, which is itself formatted as a comic of the SGR line and described in the columns within (leading to interesting questions of whether that comic, featuring characters who are actually "real" parts of the Tackleford universe, was actually published in-universe). Various postings by John Allison in early 2015 hint at upcoming publication of an actual Robert Cop comic, and several "preview" strips have been published (in between normal strips of Allison's webcomics, usually on Fridays or Saturdays), introducing supporting characters such as Detective Harper Sharp and her best friend, patrolwoman Wanda Sikorsky.
It is revealed in issue 23 of Giant Days that Robert Cop is one of the few comics that are read by Esther de Groot, along with Nahhaarratui and Protocol:Norton, two other comics from the in-universe Scary Go Round label. Esther calls these "indie stuff".