Kolchak: The Night Stalker (1974)

S1E18 The Knightly Murders

A series of murders in Chicago reveals that the victims are being slain with medieval weapons. Kolchak discovers a connection to the transformation of a small museum into a disco. The museum is home to the armor of Guy de Metancourt, a bitter man who vowed that his burial site would remain free of joy and laughter. Now, the spectral armor has come to life, targeting anyone who threatens its peace. To put an end to the rampaging knight, Kolchak must find a holy axe blessed by the pope to defeat the malevolent spirit.