The "I Want to Believe" poster.
The "I Want to Believe" poster was a poster that included an image of a UFO. The display could often be found on the wall of Fox Mulder's office. (The X-Files, The X-Files: I Want to Believe)
History
Mulder originally acquired his "I Want to Believe" poster from a head shop on M Street. (TXF: "Chinga") He had obtained the poster and attached it to the wall of his basement X-files office shortly prior to March 1992. (TXF: "Pilot") This poster was destroyed by a fire in the office in 1998. (TXF: "The End") However, Mulder acquired a replacement poster stating "I Want to Believe". It was almost identical to his previous one and he attached it to the same wall as its predecessor. (TXF: "Alpha") In 2002, the poster was the only thing not cleared out of the office but was left lying on the room's floor. (TXF: "The Truth") In 2008, Mulder stuck the poster to a wall of his home office in rural Virginia. (The X-Files: I Want to Believe)
A copy of this poster was also displayed in Blaine Faulkner's bedroom. It was presented there while Faulkner was interviewed by José Chung. (TXF: "José Chung's 'From Outer Space'")