You can cut mold off corn and eat the rest of the corn.
If you have some corn on the cob and part of it is moldy and the rest of the corn on the cob is okay and not moldy you can simply cut the mold off the corn and eat the rest of the non moldy corn.
Just like if you have a piece of fruit or vegetable or even bread that has some mold on it you can cut the moldy parts off and eat the rest.
Although we cannot digest corn fully we still eat corn as ti does have other nutrients and compounds that our bodies can and do breakdown and digest.
So while our bodies don't fully digest the corn we do still get some benefits from the corn and it does provide us with some nutrition.
Corn is high in cellulose, which is an insoluble fiber that the body cannot digest.
However, the body breaks down the other components of corn.
Chewing corn for longer can also help the digestive system break down cellulose walls to access more of the nutrients.
Corn might look untouched when it passes out in your stool.
But your body does digest parts of it.
The outer skin of the kernel contains cellulose, which your body can't break down.
The fact that it's hard to break down corn is actually ideal for the plant.
The outer coating owes its resilience to a tough fiber called cellulose, which humans don't have the proper enzymes or gut bacteria to digest.
Nutritionally speaking you could not survive on corn because if you tried to survive on a diet of nothing but corn you'd soon die of malnutrition, initially succumbing to diarrhea and mental deficiencies, depression, skin lesions and over a longer period of time, developing full-blown pellagra due to a lack of niacian/Vitamin B3.