The cloak?

[The map will be good for nostalgia and pride and boasting, and maybe someday they can use it to make a similar map of the ship, provided corridors stop moving and reforming--but then again, James is here, they can conquer anything if James is here! Even moving space corridors! But the cloak, the cloak is immediately useful, and even as he's examining James' tattoo, he's grinning at the possibilities open to them.]

Ooh, the ship must fancy you--I didn't get anything that wasn't complete crap until a few months ago, and even then it was at least half crap-- here, look--

[He shoves James' arm away so he can roll up his own sleeve, and there's a matching tattoo! It's just that the numbers are different.]

Aren't we a fetching pair. Everyone gets 'em, unfortunately, so it's not as if they're very interesting, but there's someone here that does normal old muggle tattoos, so you can still get your screeching hippogriff on fire, just without the screeching.

[And he's still grinning; his face ought to hurt he's grinning so hard. James James James. Nothing else matters!]