Rubber eraser

[Daisensei]

I was searching with the Google, using the ""キャッ党忍伝" (kyattou ninden) keyword, when I found the following URL: http://www.mandarake.co.jp/information/2006/03/03/nkn06/index.html
It refers to a offering of KNT characters rubber eraser, which image can be seen below:

Aren't they cute? The only thing wich makes me upset is the 's name was written wrongly, "Pirurun" instead the correct "Pururun".
The site seems to be in Japanese only, I didn't find a English option.

[Violet]

Those are made from the same molds as the little figures.  I don't think they would work well as an eraser, plus you'd ruin them.

http://membres.lycos.fr/spctoys/sfigures.html

[Daisensei]

The site announces that item as  てやんでえ消しゴム (teyandee keshigomu - Teyandee eraser), but it must be intended for collection rather than erasing pencil marks.