He is portrayed by Mark Sweatman.
Matthew Norvock was a henchman working for the crime lord Amunet Black. He kept tabs on Caitlin Snow, who started working for Amunet after leaving Team Flash. When Caitlin tried quitting Amunet's employ, Norvock tried intimidating her into staying, but Caitlin turned into Killer Frost and nearly killed him.
Norvock threatened Caitlin again while she was out with Iris West, Felicity Smoak, and Cecile Horton at their bachelorette party. Norvock revealed his power to summon a snake-like tentacle from his eye socket but was defeated when Caitlin transformed into Killer Frost yet again. Norvock was with Amunet whilst they showed Caitlin the new metahuman "The Weeper", and later when Amunet tried selling the Weeper to the Yakuza. Norvock escaped with Amunet after she lost her metal gauntlet.
Norvock later became the leader of Amunet's criminal organization and made a venom to enhance his tentacle. When the Flash goes after him, Norvock poisoned him and Flash phased to lose the venom. Amunet intended to kill Norvock, but Caitlin dissuaded her and argued there was some good on her, so she decided to spare him, but cut off his eye tentacle.
With Cicada killing metahumans from an arrest log provided by someone inside CCPD, Team Flash rounds up Norvock along with the remaining metas on the log. Cicada finds the meta group protected by Team Flash. While Ralph helps the metas escape, Flash and Killer Frost distract Cicada; the latter drawing blood from him for a metahuman cure.