謎ノ美兎
The [[animegao]] [[kigurumi]] version of [[Nijisanji]]'s [[Tsukino Mito]], revealed on her 2019 April Fools "stream":https://www.youtube.com/watch?v=P8WTrOlMhVk. Later nicknamed Nazono Mito (lit. Mysterious Rabbit) by fans, the mysterious figure appeared in full Tsukino Mito cosplay (including an [[animegao]] mask and zentai bodysuit).

The stream and the bizarre character were very popular among fans to the point that Nazono Mito is treated as a recurring character in Tsukino Mito's channel.
nazono mito