The smart brain wanted to cut the nut off, that was the original plan, but the dumb brain got in the way and wanted to try and muscle it off with a wrench and this is the result
It took me a minute to cut the nut off but it was to late, the damage was already done
A new nut is $10, and a new manifold is $80. If you find a used one that's a little warped but has good threads, you can straighten it. But you do have to be careful how you heat it.