'Big Brother' Alums Janelle Pierzina and Rachel Reilly Face Off on 'Snake in the Grass'

Janelle Pierzina and Rachel Reilly face a new set of trust issues on 'Snake in the Grass.'

Big Brother alums Janelle Pierzina and Rachel Reilly face a new set of trust issues on Monday night's episode of Snake in the Grass, and ET has an exclusive sneak peek! 

When the contestants' group fails to complete their scavenger hunt-like challenge, Pierzina suggests that Reilly may be the "snake" contributing to their downfall. Snake in the Grass follows a group of strangers dropped into the wild and left to figure out who in their party is the saboteur designated to undermine them. 

"There was a couple moments where I was getting really frustrated with Rachel," Pierzina says during the group's debrief. "She stepped on the string a couple times and I was like, 'What are you doing?'" 

Though the details of the string are unclear, Pierzina seems to think the action resulted in their failure to complete the challenge, meaning the snake wins. "Blame game," the show's narrator interjects via voiceover, suggesting that "snakes often try to make the mistakes of others seem intentional to hide their own lies."

Reilly is hurt by the accusation and begins to cry. "Obviously not on purpose," she defends herself to Pierzina, but the narrator doesn't take sides, labeling the tears "waterworks."

The voiceover then adds that "the most clever snakes can cry on demand to gain sympathy and dissolve suspicion." Fans will have to tune in to figure out which clue holds weight. 

Pierzina and Reilly are not newcomers to the stress of a reality show challenge, with a combined six seasons of Big Brother under their belt. They also know each other from season 31 of The Amazing Race, where they competed together. 

Snake in the Grass airs Mondays at 11 p.m. ET on USA.