bobby trap
It is used when you want to desscribe some situation, i.e. if you don't know what is actually happening out there and someone or maybe group of people deceive u to believe in sth that is not actual stuff. For example, on facebook, some sort of peoplr start sharing the fake lucky draws and other people think this is real and they can' t stop sharing these trashes again and again. Sth like that.
Look!, people started sharing the fake news on facebook. Oh, dear. It is " Bobby trap" .