Its the last judgement, and Christ is judging souls by the river.
Moses comes before him, and is upset.
“Who are you to judge me? I am Moses. I spoke to god. I led the Israelites out of Egypt. I could perform miracles.”
He holds his staff over the water, it parts. He walks down, comes back dry.
“Well, I am Christ the redeemer. I am the son of God. I had no need to part the waters, I could walk on water.”
He takes a few steps into the river, sinks to the bottom, comes out distressed.
“I don’t understand, that never happened before!”
“Well, the last time you tried it did you have those holes in your feet?"