"Off the Florida coast, teenagers (sic) come to a nearly deserted island, rumored to have 'The Fountain of Youth.' This island's owner is none too happy about that, and dispatches his daughter, Junior, to get rid of them. The island's only resident, Irving (Jack E. Leonard), is Junior's sweetie. He is sent to spy on the kids to find out what they know. Irving's twin brother and his girlfriend Camille (Phyllis Diller), are also headed for the island, with their own nefarious plans," according to the DVD sleeve description.
Baby-fattened Jayne Mansfield (as Junior) is introduced hiding her belly behind a bust of George Washington. But, the titular "Fat Spy" refers to "Bronx High School of Science" and "Fink University" stand-up comic Jack E. Leonard (as twins Irving and Herman). With a bald head, Mr. Leonard smooches Ms. Diller, while a toupee allows gets him some necking time with Ms. Mansfield. Her father is rotund Brian Donlevy (as George Wellington), who mutters something about "LSD 26"and speaks on a phallic telephone.
Hopefully, Mr. Donlevy had more blackouts than flashbacks regarding this appearance. Leonard and Diller were likely able to laugh it off. Also appearing, in a candy-striped swimsuit, pop star Johnny Tillotson (as Dodo Bronk) re-plays the "Mermaid" subplot from "Beach Blanket Bingo" (1965). None of the aforementioned cast members are seen at their best, but four stars must be awarded Jordan Christopher and the Wild Ones (Chuck Alden, Tom Trick, Ed Wright and Tom Graves) for the bathing suits and tight tunes.
"People Sure Act Funny" (an apt opener), "Nanette" and "Wild Way of Living" (the version nearer the end of the film) are highlights.
**** The Fat Spy (5/11/66) Joseph Cates ~ Jack E. Leonard, Phyllis Diller, Jordan Christopher, Jayne Mansfield
