[jonnathanson]

IANAL, and I can't really say whether a court would hold them to have been reasonably responsible for vetting this in their review process. But I do know their review process exists, and that it's very extensive, and that a court would probably not be inclined to give them a pass for ignorance -- even if they had no idea. Even if a freelancer committed fraud against them in passing this off as his own, they are economic beneficiaries of the artwork. So I don't think (?) they'd get a pass. (Would actually welcome a lawyer's input on this thread w/r/t that scenario. EDIT: A lawyer has joined in.)

Whatever the case may be, Kraft should do the right thing here. That probably means paying KrazyDad a fee or royalty of some kind, commensurate with the standard that they'd pay a typical artist whose original work graced their package. They should also issue a formal apology and pledge to improve their review process.

If Nickelodeon / MTV Networks was also involved, things get messier, and maybe there's a he-said, she-said dynamic that plays out. In any event, none of these folks are dummies. I sincerely hope, and would even expect, that they'll contact KrazyDad to make remedy.