Tigra, also known as Greer Grant Nelson, is a Marvel Comics character created by writer Roy Thomas and artist Wally Wood. She first appeared in Claws of the Cat #1 in 1972.

Tigra is a former crimefighter turned Avenger who possesses the physical attributes of a tiger. She gained her powers through a combination of science and magic, and has since become a skilled fighter and tracker.

As a young woman, Greer Grant was trained in martial arts and detective work by her police officer husband. When he was killed in the line of duty, she decided to continue his work and joined the crimefighting team known as the Cat People. Through their experimentation, they gave her the powers of a tiger, which included superhuman strength, agility, and senses.

Tigra eventually left the Cat People and joined the Avengers, becoming a valued member of the team. She has also worked with other heroes, including the West Coast Avengers and the Fantastic Four.

Throughout her adventures, Tigra has faced a variety of foes, including Kraven the Hunter, Hydra, and the villainous Dire Wraiths. She has also struggled with her own identity, sometimes feeling torn between her human and feline sides.

Tigra's character has evolved over the years, and she has been portrayed as both a fierce warrior and a compassionate hero. Her unique abilities and complex personality have made her a fan favorite in the Marvel Universe.