Mark Desmond was a strict, stern man who used G-Gnomes to manipulate his staff and security officers while willingly conducting illegal genetic experiments in the underground Cadmus labs. He is manipulative and very impatient, yet also very protective of his labs and experiments. To some extent, he manifests arrogance and hubris by considering himself and Cadmus to be one and the same. As Blockbuster he is a raging monster apparently incapable of human speech. Despite his new state he seems to be intelligent enough to stay in control and follow Icicle Sr.'s orders.
Mark Desmond had long brown colored hair tied in the back in a pony tail. He wore a standard white lab coat, glasses and had slight wrinkles on his face and streaks of white in his hair, an indicator that he may be well into his forties. After consuming Project Blockbuster his appearance transformed into a large, grotesque, dark colored monster with a daunting demeanor.
After a small fire broke out at the ground level of the Cadmus facility, three sidekicks breached security and freed his top secret Project Kr. Although Superboy turned on his liberators, Aqualad was able to communicate with him and get him to change sides just as Desmond was about to clone the three before killing them. After an extended chase through the Cadmus facility, Desmond was forced to use Project Blockbuster to restore order to Cadmus. His transformation into a hulking brute was painful, and it did not help him. He was defeated, and taken away by the Justice League.
Blockbuster was transferred to Belle Reve Penitentiary where he got work as a bodyguard for the prison Capo Icicle Sr.. He participated in a mass breakout attempt by smashing down walls that had been weakened by cold based villains. When the efforts had been halted by Icicle Jr. and Superboy, Mammoth and Blockbuster were frozen by the formers.
When the Light wanted to coerce Superboy, Miss Martian and Artemis to join them, Blockbuster served as their muscle. He kept Superboy busy when it turned out the three teens were not willing to change sides, and the fight lasted until Aqualad used Apokoliptan weaponry to trap Blockbuster in quicksand.
After the captured heroes escaped, they contemplated liberating the villains, but decided not to and find their captor first.
Kylstar's Vessel December 1, 23:58 UTC
The Justice League, Superboy, Miss Martian's valiant effort against Kylstar convinced him to treat his sentient weapons better. All captives, including Blockbuster, were released, and Orb-One explained Kylstar's motives. He was a freedom fighter who was on a mission to stop slavers who destroyed his homeworld. As a sign of his good intentions, he offered to return captives unwilling to help with his fight back to their homeworlds. Those willing to stay were promised good treatment and glorious battle. Blockbuster gleefully accepted the offer to stay.
After the others have been teleported away, Kylstar explained to those who remained that the slavers were too powerful, and the best way to defeat them was to take over the galaxy first.
Blockbuster formula: The blue serum that Desmond uses to transform himself into Blockbuster. It is unknown if the effects are reversible. The serum is stored in containment unit thirteen of the Blockbuster project.
There have been four version of Blockbuster in DC comics over the years: Mark Desmond (which the animated series version is loosely based on), Roland Desmond (Mark's younger brother, who would become a primary enemy of Impulse and later Nightwing), and two unnamed Blockbusters, one male and one female. Martian Manhunter also briefly impersonated Blockbuster during the "Salvation Run" arc.
Blockbuster's appearance in the Young Justice animated series is distinctly different from his comic appearance. In the comics he looked like a neanderthal-like man with bright colored clothing.
Young Justice is the third animated appearance of Blockbuster, who has appeared in Justice League Unlimited and Batman: Brave and the Bold. All used the Mark Desmond version; a scientist by that name also appeared in The Batman.