I have no idea what is being debated at this point.

Shouldn't the attitude be "valid until proven otherwise"?

IF you want to treat the thing that is called TES Online Lore as canon, sure.

I'm pretty sure he was making a funny joke...

But how did you kill Dagon with the Wabajack? I mean, I thought you couldn't actually attack him? Did you use a mod?

You can kill him. Not with the Wabbajack directly, but Sheogorath's most powerful artifact is necessary if you wish to attempt the feat. You see, Mehrunes Dagon qualifies as a creature, meaning he is susceptible to the Wabbajack's power, but he is also not a creature. He's more like a big walking hologram. In any case, when you see him, hit him with all of the Wabbajack's power. At first it'll appear as if nothing has happened. But then, Mehrunes Dagon deflates. If you trip past his deflating carcass, you'll find a goat or something running around named Mehrunes Dagon. Kill it, and you've won.

I actually like that as a resolution to the Oblivion Crisis and set up for SI. Sheogorsth to the rescue!

I know this is completely off-topic, but I can't let this go without asking about the implications. Do you save Martin when you do this, or does he still go through his self-sacrifice animation and turn into a statue?

If it was a more serious bug that would break the quest, it might be more awesome. But no, once you enter the Temple of the One, everything plays out normally.