Operation Brimstone was the first mission that the Suicide Squad undertaken.
The Suicide Squad intercepted Brimstone near Mount Rushmore. Captain Boomerang and Blockbuster distracted Brimstone, while the Enchantress provided cover by transmuting Brimstone's plasma, allowing Flag and Deadshot to get close enough to the monster to use a specially-created weapon to destroy Brimstone.
The advance team of agents and Blockbuster were killed, the former while gathering information in New York, the latter incinerated by Brimstone. The Enchantress attempted to escape, but was stopped by the Bronze Tiger, who was acting as team enforcer. Brimstone was totally destroyed. Overall, the mission was a success with acceptable casualty levels.