Black magic item: source of extremely nasty article from the past (4,3)
I believe the answer is:
evil eye
'black magic item' is the definition.
'source of extremely nasty article from the past' is the wordplay.
'source of' suggests taking the first letters.
'nasty' becomes 'vile' ('vile' can be a synonym of 'nasty').
'article from the past' becomes 'ye' (archaic version of 'the', the definite article).
The initial letter of 'extremely' is 'e'.
'e'+'vile'+'ye'='EVIL EYE'
(Other definitions for evil eye that I've seen before include "Supposedly harmful stare" , "Malevolent look" , "Hex look" , "Malign influence" , "Depraved optic with superstitious curse" .)