nightstalker

Noun

night-stalker (plural night-stalkers)

1. A monster or other malevolent figure that moves about at night; a shadow-stalker.
   • “Thou wilt have no need to bury me, for if I get my death he will have eaten me all dashed with blood, he will bear away my gory corpse, he will taste me; the night-stalker will devour me without mercy.”1880, The Monthly Packet of Evening Readings for Members of the English Church, volume XXX, London: Walter Smith, page 602
2. (figuratively) A person who is habitually abroad at night, especially in order to conduct illegal business.
   • [S]he accordingly proceeded with unrelaxed rapidity, startling the deer who came out into the open plots to browze, or scaring their lurking enemy the night-stalker, who, with his toils and engines, concealed himself in the adjoining bushes, that he might ensnare and carry off the fattest of the...1829, [Horace Smith], The New Forest: A Novel, volume I, New York: The Macmillan Company, page 269