Continuity Notes
The cat’s appearances were never made explicit in any of the original comics, only hinted at through sharing its name with Maguire Beck, Berkhart’s partner and the second Mad Jack. The exact nature of their relationship was clarified in Mad Jack’s entry in the Official Handbook of the Marvel Universe A to Z #6 – Volume 6.
Story
“Maguire” is a robot that Maguire Beck used to communicate with and aid her partner Daniel Berkhart while the latter was operating under the “Mad Jack” identity. The robot accompanied Berkhart on his missions against J. Jonah Jameson, and Conundrum.
After the death of the original Mysterio, Berkhart took up the Mysterio identity, and Maguire Beck took up the Mad Jack persona. The “Maguire” cat robot continued to acompany both Mad Jack and Mysterio during their plan to take revenge on Spider-Man and Daredevil, though as Maguire Beck was active in the field for at least some of this time, it is possible that the robot was now automated. Eventually, Maguire Beck was caught, and Berkhart left, taking the “Maguire” cat robot with him.