Pokémon "Rocket-dan VS Plasma-dan!" parts 1 and 2 (lost episodes; 2011)
Premiering in Japan on September 23, 2010, was the 5th generation of the Pokémon anime, known as Best Wishes! During its initial run, there was scheduled to air a 2-part episode in March 2011, ("Rocket-dan VS Plasma-dan!", "Team Rocket vs. Team Plasma!" translated, Parts 1 and 2 respectively), revolving around Team Rocket fighting Team Plasma over possession of a meteorite. However, following the devastating 2011 Tōhoku earthquake, tsunami and nuclear plant meltdown, both episodes were postponed for featuring scenes reminiscent of the disaster. As such, Team Plasma didn't end up appearing until near the end of Best Wishes!, and appearing as they did in the Black 2 & White 2 video games as opposed to their Black & White incarnations.
According to Pokémon's English dub voice director Tom Wayland, the episodes were sent to The Pokémon Company International, but never actually got to the re-dubbing process before their cancellation in Japan. Many screenshots from upcoming previews and magazines have managed to find their way online, as have various trailers that were broadcast prior to the episodes being pulled from the air.
These episodes are 2 of 4 Pokémon episodes that have never aired, the other 2 being "Battle of the Quaking Island! Barboach VS Whiscash!!" and "It's New Year's Eve! Pocket Monsters Encore". The anime has since concluded the 5th generation of the anime and moved on. Despite this, TV Tokyo said in 2011 that it will someday air, but it is unlikely that it will ever happen.
Some scenes from these episodes have been reused in later episodes.