Oscar is a cat at a nursing home in Providence, Rhode Island. It seems to have the strange ability to predict the imminent death of some of the nursing home residents.
The whole story was reported in an essay in the NEJM. See the CNN video. Oscar now has a Wikipedia page: Oscar (therapy cat).
Do Not Resuscitate (DNR) Sung to Rockstar by Nickelback
A Day in the Life of Oscar the Cat. David M. Dosa, M.D., M.P.H. NEJM, 2007.
Oscar the cat, confirmation bias and NEJM editorial judgement. Retired doc's thoughts, 08/2007.
Seizure Dogs and Death Cats. NeuroLogica Blog, 08/2007.
The Guardian: A sombre series of portraits taken of people before and after they had died is a challenging and poignant study, 03/2008.
Doctor casts new light on Oscar, "the NEJM cat", that has accurately predicted 50 deaths at a nursing home http://goo.gl/Odt7