The Armadillo Theory is the theory that once a specific arbitrary object or idea has been mentioned obscurely , or encountered randomly, that this time object or idea will suddenly appear more frequently in one's life. This is strictly based on noticing something that was already occurring in one's life, but without significance.
Once Karl mentioned to me that the armadillo was his favorite animal, I noticed how often I encountered armadillos in my daily life. This is why the theory is called the Armadillo Theory