Synchronicity. Derived from the 1984 film "Repo Man".
"Suppose you're thinking about a plate of shrimp. Suddenly somebody will say like 'plate' or 'shrimp' or 'plate of shrimp', out of the blue, no explanation. No point in looking for one either; it's all part of the cosmic unconsciousness."
Common Internet slang usage of the term circa 2004: a standalone introductory exclamation, often (but not always) connoting some degree of disbelief, shock, or disagreement, but mostly serving as an annunciation of some forthcoming, presumably more significant statement.