On Oct. 5, 2003, a grizzly bear killed and ate self-professed grizzly activist Timothy Treadwell and his girlfriend, Amie Hugeunard. Treadwell lived among the bears of Alaska’s Katmai National Park for 13 summers, videotaping some 100 hours during his stays, capturing some of the most gorgeous nature photography ever. Using this footage and interviews with Treadwell’s parents and friends, naturalists, and medical examiners, director Werner Herzog offers a prismatic sketch of Treadwell the environmental activist, Treadwell the ethnographic filmmaker, and Treadwell the insecure neurotic who felt more at ease in the wild than he ever did in society. Grizzly Man is an infuriatingly arresting documentary, taking turns into the horrendous and trite, the navel-gazing and the sublime, presenting a portrait that feels incomplete in both its aggravation and tenderness, possibly because Treadwell himself was such a mix of passion and irrationality. To wit: According to the medical examiner’s office, when the fatal attack started Treadwell was able to start his video camera but not remove the lens cap, so while thankfully footage of the attack doesn’t exist, a sound recording of it does, which Herzog himself listens to on screen but mercifully doesn’t share—and even this notoriously fearless filmmaker turns it off.