"Pokémon" has had several anime episodes removed from the rotation in Japan or the rest of the world. The most infamous of these episodes was . The episode made headlines worldwide when it caused 685 children to experience seizures and seizure-like symptoms caused by a repetitive flash of light. Although the offending sequence was caused by Pikachu's actions, the episode's featured Pokémon, Porygon, has rarely been seen in future episodes, with appearances limited to one brief cameo appearance in the movie "Pokémon Heroes" and in one scene-bumper later in season 1. Its evolutions Porygon2 and Porygon-Z have only appeared in a brief part of the opening sequence of "". Several other episodes have been removed from broadcast in Japan due to contemporary disasters that resemble events in the program; the 2004 Chūetsu earthquake, the 2011 Tōhoku earthquake and tsunami, and the 2014 Sinking of MV "Sewol" all have caused cancellations or indefinite or temporary postponements of episode broadcasts. In the United States, the September 11 attacks in 2001 as well as 2005's Hurricane Katrina led to the temporary removal of two episodes from syndication.