The Mayan's made no such prediction, but it's a great excuse for a mead anyway.
I live right in the middle of El Mundo de Maya and something that figured heavily in Mayan culture, and still does, was Cocoa. In the highlands of Guatemala pure handmade chocolate is readily available and inexpensive. One of my favorite things, which I like more than chocolate, is roasted cocoa "nibs". These parts of the cocoa pod are roasted as part of the chocolate making process and they are way yummy. I've used cocoa in Stouts and it was delicious, but maybe more sparingly in a mead...possibly in combination with some vanilla sounds good!
A cartoon attached which you really should work into the label.
They also made a hallucinogenic substance from the excretions of a particular type of toad here...another idea for ingredient just in case the world does end...at least you won't care!
And, I even hate to mention this, but corn (maize) is central to everything Mayan. They still make a fermented drink from it. A bit of corn would certainly be appropriate, but I hate to think of it in a mead, maybe just work it into the label.