Mxyzptlk, an imp with powers to manipulate reality, proposes marriage Kara, who refuses, making him take it as a challenge. Mon-El suggests killing Mxyzptlk, which she rejects. Mxyzptlk summons Parasite to attack National City before killing it in order to impress her, failing. Mon-El inadvertently reveals that another way to remove imps is by getting them to say or spell their names backwards. Later, Winn discovers a device in the DEO's collection that is connected to the fifth dimensional energy that Mxyzptlk draws power from. Mon-El attempts to use it to duel with Mxyzptlk to the death. Mxyzptlk eventually gains the upper hand and tries to kill Mon-El, only for Kara to arrive and agree to marry him. He later arrives at the Fortress of Solitude for his wedding, but Kara states that she will not marry him. Angered, he attacks her, but she stops the battle by locking the fortress down and activating the self-destruct sequence. Mxyzptlk begs for the code to stop the countdown but, after inputting the code, realizes that it spells his name backwards and is defeated. Mon-El and Kara develop romance. Meanwhile, Winn starts dating Lyra Strayd, an alien from Starhaven.