Bongcloud Attack

The Bongcloud Attack is an unorthodox chess opening that consists of the moves:
It is considered a joke opening, and is associated with internet chess humor. Its usage can insinuate that White is disadvantaging themselves, as a self-imposed challenge. Twitch streamers such as Grandmaster Hikaru Nakamura have used it in online blitz chess, including games against high level opponents, as has World Chess Champion Magnus Carlsen. The name has also been applied to other opening sequences in which one of the players moves the king on move two.
Background.
The opening's name is thought to originate either from Chess.com user "Lenny_Bongcloud" who used the opening to little success, or to more generally be a reference to a bong, a device used to smoke cannabis. The opening's usage in chess humor was furthered by Andrew Fabbro's joke manual "Winning With the Bongcloud".
The movement of the king to e2 violates accepted principles of chess strategy, by forgoing castling, impeding the movement of both the queen and the light-squared bishop, leaving the king exposed, wasting a tempo, and doing nothing to improve White's position. The lack of any redeeming feature, unlike some other dubious openings, puts the Bongcloud well outside of conventional practice. In a Twitter post, English Grandmaster Nigel Short described the opening as an "insult to chess".
High-level usage.
GM Hikaru Nakamura has used the Bongcloud Attack in online blitz games. He streamed himself using the opening exclusively on a new Chess.com account with the aim of reaching a 3000 rating. In 2018, Nakamura played the Bongcloud three times against GM Levon Aronian during the Chess.com Speed Chess Championship, winning one of the three games and losing the two others. Nakamura also played the Bongcloud against GM Vladimir Dobrov and GM Wesley So during the 2019 Speed Chess Championship, winning both of those matches. On September 19, 2020, Nakamura used the opening against GM Jeffery Xiong in the final round of the online St. Louis Rapid and Blitz tournament and won the game.
On March 15, 2021, Magnus Carlsen, playing white, led with the Bongcloud in a game against Nakamura at the Magnus Carlsen Invitational. Nakamura mirrored the opening with 2. ... Ke7, leading to a position nicknamed the "Double Bongcloud". The game was intentionally drawn by threefold repetition after the players immediately repeated moves. The game occurred in the last round of the preliminary stage of the tournament, and both players had already qualified for the following knockout stage, making the game dead rubber. It marked the first recorded occurrence of 1. e4 e5 2. Ke2 Ke7 in a major tournament.
Despite its obvious disadvantages, usage of such a "joke" opening can also have a psychological impact: following Carlsen's win over Wesley So in a 2020 blitz tournament where he played 1.f3 (the Barnes Opening) followed by 2.Kf2 a variant which has also been named as the "Bongcloud" the American grandmaster noted that losing the game after such an opening had a crushing impact.