Mo faced a challenge called Fort Locks after Ant and Dec joined camp last night to reveal he had received the most votes from viewers to take part.
At the trial, the pair explained: "You have to retrieve the stars that are locked within the hell holes built into the castle walls. The keys you need to open the locks are on chains in holes on the opposite wall. The keys and the locks are colour coded.
"When you find a star, put it in your star bag. Only stars that are in your star bag at the end of the trial will count."
Mo had twelve minutes to retrieve twelve stars.
The holes contained offal, worms, fish guts, slime, crayfish and maggots, with more fish guts and crayfish pouring in top of Mo from above.
Time ran out as he retrieved his ninth star.
Mo seemed disappointed after the Trial. He said the hardest element of the Trial was "just not knowing (what was) on the other side".
This evenings show, also saw a special live trial involving all of the celebrities.
Alongside Olympian Mo they are singer Russell Watson, Paralympic athlete Hollie Arnold, Radio 1 DJ Jordan North, soap star Jessica Plummer, actress Beverley Callard, author & podcaster Giovanna Fletcher, TV presenter Vernon Kay, journalist and broadcaster Victoria Derbyshire, ex Strictly professional AJ Pritchard, West End star Ruthie Henshall and EastEnders legend Shane Richie.
The camp have been well fed recently with Jordan last night facing a trial called 'The Trapped Door'.
Jordan had to step through a trap door and position himself on a trolley, pulling himself through a narrow tunnel on the search for stars.
Being I'm A Celeb, Jordan wasn't alone in the tunnel with maggots, mealworms crickets and cockroaches poured on top of him.
Despite his fears, Jordan won all twelve stars and was "chuffed to bits" with the result.
The group later had a delivery of squirrel to camp for their dinner for the evening.
Hosted by Ant and Dec, I'm A Celebrity Get Me Out Of Here continues each night on ITV.
As a result of the pandemic, this year's show is filming at Gwrych Castle in North Wales.
Alongside the main series, you can catch spin-off The Daily Drop via ITV Hub each morning from 6AM.