The popular mobile game Flappy Bird may be permanently grounded. Creator Dong Nguyen said yesterday he planned to pull the game from app stores, and he appears to have stood by his word. While he revealed that the game made him $50,000 a day in advertising, Nguyen also appeared stressed under the game's attention. "I cannot take this anymore," he wrote. The game was under intense scrutiny for its popularity and its visual resemblance to video game Super Mario Bros. "I can call Flappy Bird a success of mine," Nguyen tweeted yesterday. "But it also ruins my simple life. So now I hate it."