This remarkably stylized cylindrical drinking vessel is an attempt by the Maya to come to terms with foreign imagery and gods pouring out of central Mexico, far to the west of the Maya area.
The central icon is of a large bird, with feather fans and other icons that indicate that it's an import from central Mexico, from the great city of Teotihuacán. Above the image and on the rim of the vessel is the name, or at least the Maya name, of this foreign entity Waxaklajuun Ubaah Kaan,“the eighteen-headed serpent.”
When we roll out this image, we see that not only this great foreign bird but also foreign serpents or foreign snakes are indicated in these vertical panels to either side of the two birds that are depicted.
This was that foreign entity, and the Maya's attempt to use their own writing and art to come to terms with elements far outside of their own region.