A Shock to the System is a 1990 American black comedy film directed by Jan Egleson and starring Michael Caine, Swoosie Kurtz, Elizabeth McGovern, and Peter Riegert.

Graham Marshall, a long-time executive in a large advertising company, is unexpectedly passed over for promotion in favor of his obnoxious younger rival Bob Benham.

While he sympathizes with his friend George Brewster, whose dismissal in the midst of a corporate takeover created the open position, Marshall is angry and disappointed.

First he rents a car using George's corporate account and procures a bottle of heavy downers from an office courier who deals drugs.

Driving the rental car to Bob's boat, he booby-traps it by tampering with a natural gas tank and taping some matches to the door.

She retrieves the lighter from the car rental company and plans to meet Laker on the same subway platform where Graham earlier killed the panhandler.

Graham revels in his newfound prestige and freedom, having eliminated all his enemies and gotten away with it, while ensuring Stella's silence by transferring her to Los Angeles.

After Graham taunts her with the knowledge that he will never be prosecuted for it, he returns home from work one day to find Lt Laker preparing to arrest him.

[1] According to Corsair Pictures executive Frank Perry, the screenplay originally ended with the character of Graham Marshall being killed off but was rewritten because of Caine's performance.

The director Jan Egleson ultimately shot three different endings to the film, with the final version not being selected until editing during post-production.

The website's critics consensus reads: "Aided by Michael Caine's finely layered performance, A Shock to the System finds dark comedy in the cutthroat modern business world.

[5] Roger Ebert gave the film 3 out of 4 stars, writing: "A Shock to the System confounds our expectations and keeps us intrigued, because there's no way to know, not even in the very last moments, exactly which way the plot is going to fall.

The most notable fact about the picture is that the protagonist is an egocentric murderer (perhaps the adjective is superfluous), with no jot of sympathy in him; yet a considerable star accepted the role.