This is AWESOME. It even works outside of the context that it's obviously shilling for the TV show. I don't know if Batman has ever had a TV screen mounted in the dashboard of the Batmobile and surmounted by a little batty gargoyle head thing, but he SHOULD, is all I'm saying. And the poetry is quite serviceable, too. Interesting sidenote - why do you think that Robin's first thought is to wonder if the MAD HATTER is loose? I mean, yes, the letter H, fine, and 'Holy Hatrack', but surely the Joker would have been more appropriate? Anyone but the Mad Hatter, anyway. I would have done something like this:
H: "Holy Hannah!" the boy wonder says, "Can it be that the Joker is loose?" While back home, faithful Alfred cries "Heavenly days! They've forgotten to shed the caboose!"
...OK, so that last part is pure me. (For the record, I meant that they'd forgotten to unlink the camping trailer from the rear bumper of the Batmobile before starting off - but that wouldn't have scanned properly, now would it?) Anyway, it rhymes, it scans, it's got the Letter H in it - whaddaya think?