Trivia: Booker is a nod to "Good Guys Wear Black" in which Chuck Norris portrayed a character named John T. Booker. In both films Norris plays a retired military operative in a rescue mission to help his old comrades.
Trivia: When Booker is telling The Expendables about a snake that bit him and then a few days later it died, is from the infamous Chuck Norris Facts. Booker is played by Chuck Norris.
Trivia: Despite being R-rated, the film is largely devoid of profanity. This is reportedly because Chuck Norris refused to appear in the film unless all the profanity was removed from the script.
Trivia: When stuck in the mine, Gunner says he's going to blow the wall and starts digging around. Barney says he could be onto something, as Gunner has a degree in chemical engineering. Dolph Lundgren, who plays Gunner, has a degree in chemistry from Washington State University, a degree in chemical engineering from the Royal Institute of Technology in Stockholm, and a Master's Degree in Chemical Engineering from the University of Sydney.
Trivia: In the German version of the film, Arnold Schwarzenegger and Sylvester Stallone are voiced by the same actor.
Trivia: When Booker is in the helicopter towards the end of the movie, Barney Ross says to him, "I thought you were the Lone Wolf." This is a reference to the 1983 film "Lone Wolf McQuade", which also starred Chuck Norris.
Answer: The words of their chant are "Beware, beware, walk with care. Careful what you do. Or Mumbo Jumbo's gonna hoo-doo you. Mumbo Jumbo's gonna hoo-doo you. Boomlay, boomlay, boomlay, boom!" This comes directly from a poem titled "The Congo" by poet Nicholas Vachel Lindsay ("The Congo and Other Poems"), specifically the lines at the end of part I.
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