Grizzly II: Revenge.

All hell breaks loose when a giant grizzly, reacting to the slaughter of her cubs by poachers, attacks a massive rock concert in the National Park. [This sequel to "Grizzly" (1976) was left unfinished after production wrapped prematurely in 1983, and was not officially released until 2020, though a bootleg workprint version had been in circulation for some years prior to this.]