Spooktober!

Let's compromise and say it's a slightly pointy-snouted dinosaurish one.
Clothes shopping isn't really something that people do in the Wasteland, but logic states that you should make sure something fits before you buy it. Young Nick slips the costume on, although the detailed costume seems to have its own clawed feet, which does make him need to take his sandals off.

Nick comes back at this point, with a set of long-sleeved shirt, jeans, socks, and some possibly-second-hand sneakers that all seemed appropriately sized.
"Oh, founds something already? Looks cool. If we know it fits we'll just make sure this stuff does before we find the clerk and pay." says the griffin.