Teresa Vasquez, also known as Fer-De-Lance, is a supervillain from Marvel Comics. She is a member of the Serpent Society.
Little is known of Fer-De-Lance's background before she became a professional criminal. She first appeared alongside a group of fellow snake-themed costumed criminals, Copperhead, Puff Adder, and Black Racer, who were robbing a Las Vegas casino in the hopes of being recruited by the criminal gang the Serpent Society. However, they were soon opposed by Captain America (at that time known as The Captain) and his allies Falcon, Nomad and Demolition-Man, who apprehended them. As the criminals had hoped, however, the Serpent Society's leader Sidewinder teleported into their police cells and offered them membership, which they accepted.
One of the original serpents, Diamondback attempted to befriend Fer-De-Lance on her arrival at the Serpent Citadel. Fer-De-Lance expressed a romantic interest in Sidewinder, but after informing her that Sidewinder was involved with her teammate Black Mamba, Diamondback offered to set Fer-De-Lance up with another teammate, Rattler.
It transpired that the Society's new recruits were actually working for the terrorist Viper, who wanted to take over the group herself. As part of the coup, Fer-De-Lance attacked Diamondback, but Diamondback knocked Fer-De-Lance into an equipment bank, causing her to electrocute herself, and escaped.
Fer-De-Lance remained with the Society after King Cobra took over as leader, and clashed with Captain America again, among other heroes.