These days, everything that has been covered with nerdy imagery—from Shinto plaques to bicycles—seems to get the "ita" label in Japan. Heck, there are even "itachoco" this Valentine's Day. I guess a literal translation would be "painful chocolate".
Check out this itachoco gallery, collected by sister site Kotaku Japan from various Japanese Twitter users. Delicious!
2次元好きへの勝負チョコ！ バレンタインデーに「痛チョコ」を作ってみた [Kotaku Japan]