Riot's first host is Trevor Cole, a mercenary hired by Carlton Drake's Life Foundation in San Francisco. Trevor is one of several employees to be bonded with a symbiote, along with Donna Diego (Scream), Leslie Gesneria (Agony), Carl Mach (Phage) and Ramon Hernandez (Lasher). Riot and his four symbiote "siblings" are defeated by Spider-Man and Eddie Brock. The symbiotes' hosts later kidnap Brock in an attempt to communicate with their symbiotes. When Eddie refuses to aid, Trevor is killed along with Leslie and Carl; the others initially believe that Brock was picking the group off but the killer is actually Scream, having snapped from Donna's schizophrenia and the Scream symbiote's influence. The Riot symbiote later merges with Phage, Lasher and Agony to become the Hybrid symbiote, but a military group later separates them for the U.S. government. Riot's second host is Howard Ogden, a Petty Officer assigned the Riot symbiote within the Mercury Team special force. When Carnage is loose in Colorado, Howard trains with the Riot symbiote for months on specific tasks alongside Rico Axelson (Phage), Marcus Simms (Lasher) and James Murphy (Agony). Unfortunately, Howard and his teammates are later killed by Carnage in their secret base. The four symbiotes bond to Deadpool to fight Carnage, and then bond with Mercury Team's dog (the sole survivor of Carnage's attack against the taskforce) after the fight. During the "Absolute Carnage" storyline, the dog-infected symbiote came across a crying girl, Sadie, whose parents keep fighting. Sadie grows fond of the dog and after telling it the family problems has, inviting the dog inside the house. While calling for her brother Billy to see the dog, the Knull-possessed symbiotes erupt from the dog as Agony and Riot take over Sadie's parents, with Riot bonding to the father. Horrified, the kids try to escape, but Phage bonds to Billy and taunt her that they are realizing her wish and eventually Sadie is bonded to Lasher. The family then decide to go to New York and help Carnage's quest. Heidi Sladkin is a member of the Skrull Kill Krew. The character, created by Mark Millar and Steve Yeowell, first appeared in "Skrull Kill Krew" #1 (September 1995).