Bug is a play by American playwright Tracy Letts. Exploring themes of paranoia and conspiracy theories, the play tells the story of a woman who, as she spends time with a newly acquainted man in her motel room, starts sharing more and more of his paranoias. It premiered in London 1996, and was also performed around the United States between 2000 and 2004.

The play was adapted into a film of the same name directed by William Friedkin in 2006, with Letts writing the screenplay and Michael Shannon, who had played the male lead role of Peter in the original London production and in some American versions, reprising his role.

Most of the play takes place in a seedy motel room. Lonely cocktail waitress Agnes lives there, hiding from her violent ex-husband Jerry Goss, an ex-con. One night, her lesbian biker friend R.C. introduces her to Peter, a Gulf War veteran who might be AWOL. She gets involved with Peter, who grows increasingly paranoid about the war in Iraq, UFOs, the Oklahoma City bombing of the federal building, cult suicides, and secret government experiments on soldiers. He eventually draws Agnes into his delusions. The play explores issues of love, paranoia, conspiracy theories, and Agnes's slow descent into insanity under Peter's influence.

A film version of the play was released in 2006 from Lionsgate. It was directed by William Friedkin, and starred Ashley Judd, Harry Connick, Jr and Michael Shannon. Friedkin contacted Tracy Letts after having seen the play, and they cooperated on a screen adaptation. Friedkin described the film as "the most intense piece of work I've ever done".^[7] Michael Shannon had played the part on stage. Lionsgate wanted to cast an actor with more name recognition, but Friedkin was determined to have Shannon perform in the film, saying he brought a unique quality to the part.