This is a specific culture reference so not many may understand this:
In Navajo lore, skinwalkers can loiter on the roof of hogans. The word for them is Yana’gloshi.
Since Santa Claus does the same thing, the joke is “ call him yanni-Claus. “ which equates him to a skinwalker.
Funny if you understand both cultures.
Know of skin walkers but never heard the Santa reference. Creepy.