Catfish don’t have proper teeth to bite. It’s more like a gum plate with scratchy little barbs that can scrape the skin enough to draw blood.
We know that now.
There was probably no guarantee on that for the first person to try it.
It is all fun and games until the fish turns into a snapping turtle.
The catfish bites aren’t the problem. Sometimes when you stick your arm in the catfish hole there is an alligator snapping turtle in there.
Now most of the time when that happens, your hand encounters the snapper’s tail. But if the snapper is preparing to exit the hole, it turns around. If your hand goes in at that moment, you can lose the hand.