Mark Desmond developed a serum to make himself stronger, but although it accomplished this, it left him almost mindless. His criminal brother, Roland, manipulated him into committing a series of robberies, and taught him to hate and destroy Batman.
Blockbuster is also an ex-Member of Luthor/Grodd's Legion of Doom, and was killed by Killer Frost.
Blockbuster was first seen in the Justice League Unlimited episode "Kid's Stuff" voiced by Dee Bradley Baker. He, Cheetah, Copperhead, and KGBeast were robbing a gold vault. While KGBeast chased after Batman,Superman entered the vault to find Blockbuster already inside. Yelling to his partners in crime to pound the Justice Leagues' heads,Blockbuster rushed at Superman and punched him. Superman responded by hurling Blockbuster into a wall. Superman then dragged Blockbuster's limp form over to where KGBeast and Cheetah lay in the middle of the hallway,having been deafeated by Batman and Wonder Woman,who roped the villains up with her Lasso of Truth,only to be transported to another dimension with the other adults. Blockbuster found himself next to KGBeast,but unlike the latter,who showed barely any reaction to the change in surroundings,Blockbuster cowered behind a rock. Later, Blockbuster was shown to also be a member of the Legion of Doom in the series.
Blockbuster was also present during the attack on Gorilla City with The Puzzler, but he was easily defeated by Superman once again.
During the two-part series finale, Lex Luthor tried to resurrect Brainiac by ordering the Legion to transform the base into a spaceship, so that they could travel to the site of Brainiac's ruined asteroid base. With Tala's help, Grodd attempted a coup to retake control of the Secret Society, leading to a battle between members loyal to either Grodd or Luthor.
During the mutiny, Blockbuster and a majority of the Legion of Doom sided with Grodd. Blockbuster went after Luthor along with Major Disaster, but Blockbuster's attempted attack on Luthor was thwarted by Sinestro. As the battle between the two factions continued, Blockbuster came under attack by Heatwave, only to be saved by Silver Banshee hitting Heatwave with her high pitched shriek.
When the mutiny was over, Blockbuster and the other surviving loyalists of Grodd were betrayed by their ally Killer Frost and frozen to save herself from Luthor's wrath. Blockbuster and the other frozen loyalists were subsequently destroyed when Darkseid blew up the ship.
Because of the Bat-Embargo to limit or ban the use of Batman related characters from any media source outside of the Batman Begins movie franchise and The Batman animated series meant that only more obscure Bat-villains such as the KGBeast (Justice League Unlimited),Clock King, Gork, Sportsmaster, Blockbuster or Copperhead would appear in the DCAU.