Someone who you and eventually many of your friends added to facebook because of association or suggestion by facebook, acts like a Gremlin, when water is added.... they continue to randomly post comments on your posts even though you never speak to or post comments on their posts. You don't really care about or like the person, but they continue to post the most obscure or random comments on people's posts or pages although no one acknowledges or responds
Damn, can you believe that Facebook Gremlin Shane just posted on like 6 different people's pages again! Does anyone even know that dude? He pops up all the time and even after I deleted him, he still finds a way to pop up on everybody's posts!