Which character is the Hawkins Lab test subject known as Eight?

The Hawkins Lab test subject known as Eight is Kali Prasad.

Kali was one of Dr. Martin Brenner’s numbered child subjects at Hawkins National Laboratory. Like Eleven, she was taken from her family and subjected to experiments designed to develop psychic abilities. Her laboratory designation was 008, which led to her nickname, Eight.

Kali’s power differs from Eleven’s telekinesis: she can create vivid illusions that alter what other people see and perceive. After escaping the laboratory, she formed a revenge-driven group in Chicago and targeted people connected to Brenner’s experiments.

A common mix-up is confusing Kali with Jane Hopper, Eleven’s birth name and laboratory number 011. Terry Ives is Eleven’s mother, while Angela is a California schoolmate who bullies Eleven; none of those characters is Eight.