Viewers originally voted for Iain to face the underwater challenge during the first week of the ITV jungle show.
However, the radio host struggled to catch his breath and quit moments in, claiming the sunken chambers were too cramped for his tall frame.
Rather than waste the Trial, bosses gave it a second go yesterday - and this time one of the smallest campmates took part.
At Amir Khan's suggestion, Dennis agreed to try it out, saying: "I’m quite a positive person. I’ll definitely have a go as much as I can."
Hosts Ant and Dec introduced him to the Temple of Gloom, an underwater structure of tunnels and chambers - some with air pockets, some flooded.
Dennis had ten minutes to make his way from one end to the other, while collecting stars representing meals for camp.
"As this is a Bushtucker Trial, there is a high chance you won’t be alone under the water," Dec reminded him.
The 5ft 6in footballer sped through the first two chambers, collecting four stars among water dragons, spiders and crocodiles.
Ant advised him to be "very careful and very slow" as he entered the third section, which contained thirty pythons.
Nonetheless, he quickly collected two more stars and made it to the final chamber, full of mud crabs, eels and yabbis.
Although Dennis yelped when "something nipped my foot", he bagged the final stars and made a swift exit.
Ant and Dec were astonished that he finished in "record time", the latter revealing: "You had ten minutes to do that Trial, and you did it in five."
Dennis attributed his success to his small size and teased Dec, unaware that the Geordie host has been repeatedly calling him a "very small man" in a running gag.
"I’m pleased about that, it’s because I’m small," he said. "Me and you would be perfect!"
The celebs were thrilled when Dennis returned with all eight meals on offer.
Iain hailed his victory, saying: "Dennis has defeated the Temple of Gloom that defeated me, and has been defeated itself by the mighty fish-like wonder of Dennis Wise."
I'm A Celebrity… Get Me Out Of Here! continues nightly on ITV until Sunday's grand final.