Spidey Easter Egg - Spidey ...Earth X Oneshot Special

in the early prints of this alternate spiderman comic there was a hidden message to the then-editor-in-chief Bob Harris.
It is hidden in a bookcase ... the message is scrawled along the spines of the books and reads something like " so long Bob Harris you son of a b**ch ha ha ha" ..something like that. Bob Harris was leaving and the artist hadn't liked him.
The comic went to print and Marvel realized too late what had happened. They instructed comic shop owners to destroy those copies and sent out batches of replacements. Of course many copies were not destroyed.
Why is this egg cool? Because if you have a copy with the message still on the book spines it's worth considerably more than you paid for it..