
The important thing to remember is that you are dealing with a person who has essentially placed a twig on their head and expects you to believe they are a tree. Armored in that level of "confidence," almost anything you say will be construed by them as evidence that their tree disguise is working, so you will have to be very specific and to the point in addressing exactly what they're doing and why it's not fooling anyone.
Subtlety and sarcasm are great tools but there is no way in hell they will get through to this poor sap. Unless you're just toying with them for your amusement, the best way to put an end to it is just to be direct. Point them to this guide if necessary, explain that you know what they are doing, and that it is so obvious it can be seen from space.
Chances are they will just end up placing more twigs on their head, praying fervently that this will succeed, but at least you gave it your best shot.

Cracked Talk on | Internet Argument Techniques
I'm new here, but I joined up just to ask if something I've been seeing counts.
The tactic where the arguer has a LOT of people shooting down every "point" he made, but there's one/a few people he sees as weak links. Whether they misspell something, don't have a point at all, or what ever, these become his sole target for making their point.
All those who prove him wrong he either ignores like they were plague carriers, or has nothing but insults for them.
Am I the only one who had seen that?
My first post, and I missed tunnel vision after reading over it, 3 times?
Don't worry, happens to everyone. Don't feel like too much of a doodle for it.
And no. Trust me, you're not. It's like supertunnelvision, yeah, but the way you put it makes more sense to me. It's even worse when NOT on the internet.
(says to self inquisitively)Cocktopus? hmm... its GENIUS!
hahaha this is soooo true! I have even used some of these techniques myself in forums, because they usually get people more worked up. I be trollin', they hatin'. LOLOL