Slipknot was a minor villain that fought Firestorm and was promptly put in custody by the government.
Slipknot was one of the chosen incarcerated villains to join a mission for the Suicide Squad. Like all new, and untrustworthy, members of the Suicide Squad, Slipknot was forced to wear an explosive bracelet so they could make sure he wouldn't try to run away.
On that mission, Captain Boomerang convinced Slipknot that the explosive bracelet was only meant to scare them and didn't actually operate. Secretly, Captain Boomerang only wanted to know for certain if the explosive bracelets would detonate and needed someone else to test it. Slipknot lost an arm on the mission. He was believed to have died out in the swamp.
During the events of Identity Crisis, Wonder Woman and Green Arrow questioned Slipknot to find out if he knew anything about the death of Sue Dibny, but it was determined that he had no involvement. Slipknot became a converted member of Kobra some time after his mission with the Suicide Squad. He still only has one functioning arm.
During Infinite Crisis, Slipknot was captured by OMACs, who have scheduled him and dozens of other super villains for execution. He escapes when Robin defeats the OMACs, but is quickly captured again and put into U.S. Army custody.
Final Crisis Aftermath
After the events in Final Crisis, Mark Richards, the Tattooed Man, has become the protector of Liberty Hill, and Slipknot along with Cannon are hired to take him out by the mysterious Mister S. Cannon and Slipknot blindside Richards after he saves his son, Leon from a drive by shooting. Richards easily takes out Cannon, but Slipknot is able to catch Leon. He gives his father an ultimatum, let him and Cannon escape or he'd kill Leon. Richards has to let them go, a choice he will always regret.
Then later after Richards seemingly kills Cannon and it is revealed that Mister S is in fact the Tattooed Man's, thought to be dead, little brother Devon. Slipknot is the one who throws Mark beaten body back on the streets, for the people of Liberty Hill to see.
When Mark gets his act together and comes back after Devon, Slipknot is there. Slipknot's right arm, which was replaced with a bionic appendage after his run with the Suicide Squad, is destroyed by one of Mark's tattoos. Mark then leaves Slipknot for dead much like Slipknot did to him earlier.
Somewhere between Aftermath and Titans, Slipknot kills Leon, as retaliation for what Mark did to Cannon and to his arm.
Titans: Family Reunions
In order to gain Tattoo Man's loyalty to the new version of Titans, Deathstroke captures Slipknot for Richards to kill. Deathstroke chains Slipknot to a chair and shows Richards but when Richards enters the room Slipknot is loose. Deathstroke tells the rest of the team that Richards would never be able to live with himself for killing a man in cold blood.
Slipknot is able to get the jump on Richards, but when he taunts him about killing his son, Richards only gets enraged. Richards knocks Slipknot into the Holo-room, where Richards turns on the hologram of Liberty Hill, the home of there last battle.
To the chants of "Kill Him" from the hologram residents of Liberty Hill, Richards beats Slipknot with his tattoos until he has him wrapped up. Slipknot tries to plead saying "Capes Don't Kill" and Richards response with "You hear that...I just took my cape off." He then wraps his barb wire tattoo around Slipknot's neck and decapitates him.
For more information see: Flashpoint
Slipknot is incarcerated for life, in the flying prison, The Hall of Doom, for the violation of penal code 756. He is one of the inmates attacked by Amazo, the prison's head guard, when Heatwave and the others first start their breakout.