Heavy metal legend Zakk Wylde -- one of the greatest thrasher guitarists EVER -- claims he's "terrified" of an obsessed fan who recently left a "sacrifice" at his home ... this according to court docs obtained by TMZ.
Wylde -- founder of the heavy metal band Black Label Society -- filed a request for a restraining order against his 20-year-old neighbor ... claiming the guy has been stalking and harassing him a while.
According to the docs, Wylde recently called police to respond to an incident at his home involving the neighbor -- which resulted in cops placing the neighbor in a 72 hour hold for mental evaluation.
Wylde claims the neighbor was "deemed mentally ill" -- and diagnosed with bipolar 1 disorder.
An L.A. County Superior Court judge approved a temporary restraining order against the neighbor -- requiring him to stay at least 100 yards away from the rocker and his family.
Both sides are scheduled to appear in court on the matter on Friday.