The Amber hallucination is a term used to describe House's hallucination of Amber Volakis, James Wilson's girlfriend who died in the Season 4 finale, Wilson's Heart. She began appearing as an hallucination, congratulating House on solving another case. She eventually haunted him during the last few episodes of Season 5. At first House was amused but things got very serious when Chase nearly died due to allergic reaction to the type of body butter that a stripper at his bachelor party used, leading House to assume that since Amber was part of his subconscious, he was trying to kill Chase too.