It interacts with the post-Scratch kids, primarily Jane. Unlike Jade's relationship with Bec (Earth's pre-Scratch first guardian), Jane doesn't see GCat as a guardian or protector, or even pet or friend. "He's just a feisty stray who likes to meddle with [her] life, then vanish for weeks at a time". For example, Jane recounts an incident in which GCat teleported her into a random field on the other side of town .
Curiously, when Jane was preparing to enter The Medium in [S] Jane: Enter, GCat stopped Dirk's auto-responder from prototyping Poppop's stuffed corpse by warping it into space. This may be because the post-Scratch session was destined to be a void session, and any action deviating from that would result in a split doomed timeline, which GCat was probably trying to prevent.
Years in the future (but not many), after Jane and Jake have entered, the Condesce would use her new powers to control the GCat in a fight against Dirk's Bro and Roxy's Mom.
Hundreds of years in the future, when Roxy is about to appearify a Colonel Sassacre's, GCat teleports into the room, provoking Jaspers into attacking it before teleporting away, and causing Rose's former cat to get crushed by the giant joke book. He then watches as Roxy sends him back to Rose through the lab machinery , only to abscond as soon as she is attacked. As she tries to escape, through the fenestrated plane, he warps it out and sends it to Dirk's apartment - unplugged.
He is also seen in LOPAN during Jane's and Roxy's preperations for Jane's upcoming birthday. This implies he either entered the Medium alongside Squarewave or Sawtooth, or had alternative means of entry (potentially connected to the Condesce).
One striking difference between God Cat and Becquerel is that GCat interacts with multiple players of the session instead of just one, much like another post-Scratch first guardian we know of. GCAT is also seen at an unknown point in time resting in the lap of the Condesce and being petted, in a traditional villain motif.
It is currently unknown what GCat's true feelings, motivations, or agendas may be, with regard to Jane or anyone else. Nobody even knows its name (see the section below). However in the future the Condesce seems to remain in control of him and his actions, however it is unknown when exactly she gains her new powers, leaving it unknown if she is responsible for past actions of the GCat.
Jane believes the creature doesn't have a name, and as such she and her friends refer to it as GCat for short. This name's connection to the four nitrogen bases that form DNA (Guanine, Cytosine, Adenine and Thymine), not only connects it to the naming convention of the various online handles, but also, more delicately, to how the DNA sequence involved in Bec's creation was recorded with a substitution of these letters by those used in the word MEOW. This had been due to be Rose's subconscious association of the code with the "secret" Jaspers left her before his disappearance. Whether these aspects of the name are anything more than in-jokes remains to be seen.
The exact origins of GCat have yet to be revealed. However, the process for the creation of First Guardians is known and would suggest that a cat that has already been seen or yet to be introduced would be the Ectobiological origins of GCat. This leaves a limited pool of cats. Looking much like a regular Earth cat would suggest a relation to Jaspers; another possibility is that like Doc Scratch he has multiple ectobiological parents, and that Jaspers or another cat was merely added to the previous parent Halley. This would explain why Gcat's body structure is very similar to Bec's. There may also be a relation to Mutie. The source of the genetic sequence that all First Guardians share is very likely written in the notebook that Roxy managed to appearify from Jake's room, as it appears to contain a genetic sequence encoded with the word BARK, mirroring the MEOW code used to create Becquerel.
As the death of Jaspers is caused by GCat momentarily appearing in Roxy's room and provoking him – an incident previouslyreferred to more obliquely – this may be GCat's way of fulfilling the necessary task of all first guardians having to ensure their own creation. This would imply that GCat's ectobiological parent may be Jaspers, and in getting Jaspers killed, it is ensuring that he is paradoxifiable – a requirement of ectobiology.
The line that "everybody has opinions, but nobody can agree on a good name" is likely a jab by Hussie towards the forums, where users were trying to come up with various different names, such as Curie or Sievert, but no consensus had been reached.
He has a green tongue, which may or may not be atypical among First Guardians, or significant at all: Doc Scratch most likely has no tongue since he has no face, and the inside of Bec's mouth is shown to be white, although this may be a question of stylization as Bec's mouth was shown in a symbolic manner, and as such details may have been omitted.
The fact that God Cat teleported Poppop to outer space to stop a prototyping is a reference to Bec doing the same thing to Jade's Grandfather.