Ikuradon-chan is part of Anpanman's roster of quirky food-themed characters—specifically, she's one of several whose entire head is literally a dish. In her case, it's a bowl of ikuradon (salmon roe rice bowl), with her head filled with salmon eggs.
She debuted on September 17, 2004, in the episode "Anpanman and Ikuradon-chan" and has made plenty of appearances in the anime since then.
Content compiled by AnimeList.moe from publicly available sources.
