>>149423349
I've looked through other style guides, while there's no requirement for all stock art to have his signature all SB shit needs to say "created by Stephen Hillenburg" somewhere on the packaging
The less cynical amongst us may think this is standard practice but it is not; as far as I know it's only present on Spongebob, Fairly Odd Parents (and presumably other Hartman shows) and the K-C cartoons, no requirement is listed in the Invader Zim style guide