Always optimistic and resilient as a dancer, UC Berkeley sophomore and intended forestry major Chris Cosby died Monday from spinal cancer. He was 20 years old.

Cosby was diagnosed with glioblastomas, a malignant form of brain cancer, in April 2015. Despite the successful removal of virtually all of the tumors in his brain as a result of chemotherapy and radiation treatments, Cosby was notified in December that tumors had grown in his spine, according to Heather Michaelson, Cosby’s technical theater teacher in high school.

“In his twenty short years Chris touched the lives of many people from many different walks of life; everyone that met Chris had their lives enriched in some way,” said Jeff Cosby, Chris Cosby’s father, in a Facebook post. “He wanted everyone to know he was thinking of them even up to the last moments of his life and that he cherished all the moments even if he was taken from us far too early.”

Michaelson met Chris Cosby in summer 2012, when Cosby volunteered to work in his school’s theater department. During his junior year, Cosby officially enrolled in Michaelson’s technical theater class.

“It was clear from the beginning that he was a special guy,” Michaelson said. “He always went above and beyond.”

As president of Los Alamitos High School’s stage crew, Cosby carried an aura of respect among students, according to Tyler Adams, his high school friend. Cosby joined his school’s show choir team as a member of its technical crew and later became a performer, shocking everyone with his charismatic onstage presence, Adams said. Cosby became co-president of the choir’s technical crew with Adams during their senior year.

“He was loud in voice but quiet in personality … like a gentle giant,” Adams said.

Cosby’s interest in performance followed him to college. He was very involved in UC Berkeley’s dance community, joining two groups — the Movement and Manly Men — in spring 2015, according to Manly Men member Raymond Truong.

Cosby went to every single office hours meeting for the Movement and had a great work ethic, according to Jon Mitsui, Cosby’s choreographer in the Movement. As a result, Cosby was given a character role in his team’s dance performance in the same semester.

“He had a contagious attitude, but in a good way,” Mitsui said.

Kirsten Flores, a member of the Movement alongside Cosby, said he worked really hard for what he was able to accomplish, especially after undergoing treatment for his cancer.

Cosby also carried a large presence in Manly Men, according to Truong, who added that Cosby always volunteered wholeheartedly to execute his outrageous performances with as much effort as he could.

“Without Chris, the team would have been far less fun,” Truong said.

Cosby followed his passions, which led him to make great friends and memories at UC Berkeley, Michaelson said.

“It’s really hard to imagine that he’s not going to be here doing things for the world,” said Spencer Woolard, another high school friend.

Contact Roann Pao at [email protected] and follow her on Twitter at @roann_pao”