Ooh, tough call.
I think Elan just made two beautiful rolls: sense motive + bluff. And sarcasm, yes, I think. I re-read the strip several times, and when I read sarcasm into his words, it made the most sense.
And V? Reminded me of the fact that in any wizard's arsenal of greatest weapons is a feat called Greater Show-Off. Better known sometimes as "Unsightly fools who have enraged me! Shudder in my presence! Cover before my power! Flee before my... Illusion!" (Which is the least obscure reference I can come up with at the moment). This looks like Greater Show-off... Failed abysmally. And any wizard worth their salt knows when to back off after that.
I have the impression that the conversation between Elan's and Vaarsuivius' players went something like this:
"Oh, now you've done it. My hands and eyes start glowing with arcane power..."
"You are so bluffing."
"Are too. Don't even bother rolling."