What is RickRoll?
It is a prank and internet meme involving an unexpected appearance of a music video "Never Gonna Give You Up" by Rick Astley which hit number 1 in top 100 in March of 1988. It also has a long journey on how it became a meme, it started when it gained popularity on the internet after it's appearance in "It's always sunny in philadelphia"
Then the creator of 4chan created a word filter which changed the word from egg → duck which started a new meme when it changed the word eggroll to duckroll and this img popped up people started generating links which would misdirect the people to this image and when GTA 4 came out and people started linking to it's trailer but it took them to this video and thus Rickrolling was born.