Pure Hallucination
This entry is a placeholder. I am currently cataloguing both the fake citations that are shown in real cases and the citation graph of real AI hallucination cases. The canonical write-up is still in progress and is currently incomplete, with stub articles generated from the data in the Interactive Map of AI Hallucination Sanctions Cases. Please don't treat it as final or authoritative yet.
Definition
A pure hallucination is an entirely fabricated citation — a wholly fictitious case that does not exist at all. It is distinct from a mutant / synthetic citation (which splices together real citation elements into a false combination) and from a hallucinated summary (a real case whose holding or quotation is misrepresented). Pure hallucinations are the most famous and most obvious type — the kind at issue in the classic Mata v. Avianca — and the easiest to catch, because the case simply cannot be found in any database.
Why it matters
Worked examples
Cases with examples of this failure mode
- Mata v. Avianca (S.D.N.Y., 2023) — 6 instances
- Zeng v. Chell (S.D.N.Y., 2024) — 2 instances
- Smith v. NYC, 2022 U.S. Dist. LEXIS 67890 (S.D.N.Y. Mar. 15, 2022)
- Brown v. Doe, 2023 U.S. Dist. LEXIS 12345 (S.D.N.Y. Feb. 10, 2023)
- Lafayette v. Blueprint Basketball (Vermont Superior Court, 2024) — 2 instances
- Pavlovich v. National Life Insurance Company (VT, 2010)
- State v. Dalco Electric, Inc. (VT, 2015)
- Kasten Berry Inc. v. Stewart (D. Kan., 2024) — 1 instance
- Novitzky v. TransUnion (C.D. Cal., 2024) — 2 instances
- Dowlah v. PSC-CUNY (New York Appellate Division, 2024) — 1 instance
- Anonymous v. New York City Dept. of Education (S.D.N.Y., 2024) — 1 instance
- In the Interest of R.A. (Iowa (State Court), 2025) — 2 instances
- Garner v. Kadince (Utah Court of Appeals, 2025) — 1 instance
- Windham renovation dispute (NH) (New Hampshire Superior Court, 2025) — 1 instance
- Withers v. City of Aberdeen (N.D. Miss., 2026) — 1 instance
- Prososki v. Regan (Nebraska Supreme Court, 2026) — 1 instance
- Kennedy v. Kennedy (2019)