The off-camera shenanigans of Howie (St. Elsewhere) Mandel and Ted [Cheers) Danson nearly outnumbered their antics on film in Blake Edwards' slapstick comedy A Fine Mess. At one point Mandel planted a firecracker in Danson's dressing room; Danson retaliated by rigging Mandel's car with a smoke bomb. The movie crew then switched the bomb to Danson's car where it went off. To thank Columbia Pictures' chief Guy McElwaine for letting them frolic on the set, Mandel and Danson, aided by six burly crewmen, transported a 40-foot-long Fiberglas elephant and matching 15-foot saber-toothed tiger to the front lawn of McElwaine's Beverly Hills home early one morning. "We knew you had everything else," joked Mandel when McElwaine appeared at the door. The movie mogul promised to find an appropriate thank-you gift. [P] Tina Turner is writing a book, I, Tina, with the help of Kurt Loder, who did the Rolling Stone cover story about her last October. The bio, due out next year, will tell all about Tina's travails with ex-hubby Ike, who, meanwhile, is peddling some old tapes he recorded with Tina in the early 70s. It seems Ike, who hasn't had a hit in years, is looking to cash in on Tina's comeback.... [P] The producers of St. Elsewhere are scouting locations in Ethiopia and Kenya where they may shoot famine-related episodes for next season.... [P] Director Paul Mazursky has cast tutti-frutti rocker Little Richard as a record exec named Orvis Goodnight in his forthcoming film, Down and Out in Beverly Hills, which stars Bette Midler, Richard Dreyfuss and Nick Nolte. [P] In director John (Excalibur) Boorman's film The Emerald Forest, due out in July, his 18-year-old son Charley had his work cut out for him. Cast as an American engineer's son who's raised by Amazon Indians, Charley did many of his own stunts, including scaling an 18-story building and dropping over a 50-foot waterfall. His least favorite scene was a re-creation of a tribal ritual, during which he was covered with 2,000 large biting ants. The insects' pincers were supposed to have been removed before filming, but, says Charley, "a few drew blood. They were crawling into my mouth, my eyes, my nose. I was so freaked out, the rest of the movie was a piece of cake by comparison." [P] It wasn't critical for Dean Butler to keep his pecs pumped up when he played Melissa Gilbert's husband on NBC's Little House on the Prairie. But when he got word he'd have to go shirtless in Gidget's Summer Reunion, a syndicated TV movie airing this month, Butler enrolled at Gold's Gym near Santa Monica and started working out with a trainer. Butler, 29, who plays Gidget's husband, Moondoggie, was intimidated because tennis pro Vince Van Patten, 27, was cast as a local surfer in the movie. Says Butler, "Vince is a world-class athlete. When he takes off his shirt, people take notice. I didn't want to embarrass myself." Satisfied with the results of his 12-week regimen, Butler adds, "There's something nice about being able to take your shirt off and have a chest there." [P]