The character Peppy Hare shouts "Do a barrel roll!" repeatedly at the player. This became a massive internet meme in the mid-2000s, leading to Google implementing the code on their search engine in 2011.
: To perform it twice, type "do a barrel roll 2 times" into the search bar. do a barrel roll 2x
To give you something concrete — if your request is — here's how you'd achieve "do a barrel roll 2x" in JavaScript on any webpage (as a demo): The character Peppy Hare shouts "Do a barrel roll
: This trick requires a modern browser with HTML5 support (like Google Chrome or Mozilla Firefox) to work properly. do a barrel roll 2x