It didn't really come off as an ego trip to me... And I don't like it when 'well, he's crazy' becomes a catchall excuse for any sort of bizarre behaviour. There are specific kinds of crazy, and it's best to pick a flavour and stick with it.
(Feels a bit sleazy talking about it after Hansie's already more-or-less fixed it :/)
I think there's still sort of a problem in that Mr. Crazy still kind of drops a blatant hint as to what happened, and simply doesn't explain it further. It's not as bad as 'okay, now that you're at my mercy, I will explain to you exactly how and why I put you in this situation while your creepy friend rushes in to help', but it's still pretty strange for him to bring it up, even more so now that he just drops it without going anywhere with it.
But now I'm just nitpicking, and I'm too tired to really analyze anything properly right now.
EDIT: I think I've got it now... If it's intended as an ego trip, then I think the general gist of his comment should be less 'btw, I did something to you but I'm not telling what' and more 'lolololol u walked right into my trap I'm the bestest villain EVAR JUST AS PLANNED!!!!!'. For him, it's not what he did that's of interest to him, it's that him doing it now makes him the BESTEST VILLAIN EVAR, at least in his own mind. He'd probably drop at least a few hints while raving about it, but it's not really what he cares about.
EDIT II: Should probably disregard that entire last edit, honestly. Need sleep badly