It's probably his own personal stamp, from a set he made himself. That's why he's so angry; his feelings have been hurt. 'Goddammit! I spent so much time making those things! It's the little details, y'know? The little details that make a caper sing. I spent HOURS posing in front of the mirror with a sketchpad, trying to get my grin just right - I mean, look at that shadow on the bicuspids; it's a work of art! And just WHO had to find out what precise shade of green my hair is? It's Midnight Lime, that's what it is. I know this because I had to hunt through EVERY single paint sample in the store before I got it right. I got eyestrain, I did! It took days and days to find someone who'd print them up for me, and then I had to send them back because of that printing error, and THEN I - oh, drat! Weeks, it took! WEEKS, getting them perfect, just so I could use ONE of them for this one special moment! And what does she do? She laughs! *his lip trembles* No one appreciates an artist these days."