'Naked & Afraid: Last One Standing' Survivalists Eat Elephant Poop Seeds

"Naked and Afraid: Last One Standing" is back with its brown-out episode -- survivalists chowing down on elephant poop-covered seeds.

TMZ snagged the first-look exclusive clip -- nothing triggers the survivalists' gag reflex like what they had to endure to win the $100K grand prize in Africa -- sifting through hardened elephant dung and chewing the seeds out without rinsing.

As you see, they all rush over to the dung piles for the challenge ... extracting the tiny seeds. Then, they ingeniously build a bird trap using the chewed seeds as bait.

The poopy seeds are no delicacy. Contestants gag like crazy as they describe the scatological experience.

You don't really want to watch it, right? But, you can't look away either, 'cause the survivalists are so desperate to win massive ostrich eggs -- yeah, it's not filet mignon, but it's something to eat.

Check out how it all goes down when the episode drops this Sunday at 8 PM ET/PT on Discovery Channel.