|For other uses, see 0-8-4 (disambiguation)|
- "I don't even know where we are going."
"Peru. That's where the 0-8-4 was reported."
"And an 0-8-4 is?"
"Object of unknown origin, kind of like you. Team goes in, determines if it's useful or poses a threat. Last one turned out to be pretty interesting."
"What was the last one?"
- ―Skye and Phil Coulson
An 0-8-4 is an object of unknown origin detected by S.H.I.E.L.D.. Depending on the situation, either a small or large group of agents are sent to determine what the 0-8-4 is, and how it could be used.
The code "0-8-4" derives from the identification number used on the case containing the first object of unknown origin encountered by the Strategic Scientific Reserve, the precursor of S.H.I.E.L.D. The object was a Diviner obtained by Peggy Carter during the raid of the HYDRA Research Facility in Austria in 1945. It was most likely the eighty-fourth item catalogued during the raid.
Leo Fitz explained to Skye that he had never experienced an 0-8-4 being a person, though it was possible. He elaborated by saying that he has read about weapons, spacecrafts, and energy sources labeled as 0-8-4s, citing that the only characteristic they had in common is that all were dangerous.