Greer Grant Nelson, known as Tigra, is a superheroine in Marvel Comics who originated as the costumed vigilante The Cat. Created by writer-editor Roy Thomas and artist Wally Wood, with early stories by Linda Fite, she debuted in The Claws of the Cat #1 (November 1972). Initially a human enhanced through experimental procedures by Dr. Joanne Tumolo, Greer gained cat-like agility and senses to combat crime following the murder of her police officer husband. After a confrontation with Hydra agents exposed her to lethal alpha radiation, Tumolo—revealed as a member of the ancient Cat People—facilitated a mystical ritual that bound Greer's soul to a feline exemplar, transforming her into the anthropomorphic Tigra, debuting in this form in Giant-Size Creatures #1 (July 1974).

Tigra possesses superhuman physical attributes derived from her feline transformation, including enhanced strength, speed, agility, durability, heightened senses, razor-sharp claws and fangs, and a prehensile tail. She also exhibits accelerated healing and limited mystical affinities tied to the Cat People. In her early adventures, Tigra transitioned from solo stories in titles like Marvel Chillers and Monsters Unleashed to guest appearances alongside characters such as Werewolf by Night, Spider-Man, and the Fantastic Four. Her dual nature often created internal conflict, balancing human intellect with primal feline instincts.

Over the decades, Tigra achieved prominence through membership in the Avengers, where she was coerced into candidacy by Moondragon before formal induction, and later as a founding member of the West Coast Avengers. Significant developments include struggles with her bestial side leading to temporary alliances with villains, a 2002 miniseries exploring personal identity, and more recent narratives involving romantic ties, police training, and appearances in events like Civil War and collaborations with figures such as Moon Knight, solidifying her as a resilient and multifaceted presence in the Marvel Universe.