Now, we have the Chinese version of that old saying, "I'll bet I can".
A fellow in Nanjing, China showed up at a hospital, saying his stomach hurt.
Doctors took X-rays and that's when the doctors found the five inch knife in his stomach.
He said he bet his friends he could swallow the knife and after he put it into his mouth, it somehow went down his throat.
Why he didn't expect this, we don't know.
The operation to remove it took about an hour.
When he was interviewed by Chinese state TV, he said that he had also swallowed a steel bar before and that also had to be surgically removed.