The Mexican president posted a photo of what he thought was a mythological 'alux' on social media, adding "everything is mystical".
President Andres Manuel Lopez Obrador appeared to be serious when he posted the photo to Twitter on Sunday, which has now amassed over seven million views.
Mr Obrador wrote: "I share two photos of our supervision of the Mayan Train works: one, taken by an engineer three days ago, apparently from an alux."
The photo, taken at night, is of an unidentifiable creature at the top of a tree with white eyes and hair.
According to traditional Mayan belief, 'aluxes' are small, mischievous beings similar to elves that live in forests and fields.
They are tricky spirits, and are said to prank people and hide their things.
Some people leave small offerings to appease them.
The second photo was of a "splendid pre-Hispanic sculpture in Ek Balam", added Mr Obrador, ending his post with "everything is mystical".
The president has expressed his respect of indigenous cultures and beliefs for a while.
Engineers and workers are in the Yucatan peninsula, constructing a tourist train that the president pledged would operate by the end of 2023.
It was in this very peninsula and the surrounding areas that the ancient Mayan civilization reached its peak from 300AD to 900AD, and descendants are said to still live in the region.
Many have retained the Mayan language, clothing, traditional foods, crops, religion and medicine practices, despite the Spanish conquest in the 16th century.