With “Tobidase! PC-Genjin” (飛び出せ!PC原人), another popular Hudson Soft series, “Bonk”, was once planned to make an appearance on the Nintendo Virtual Boy, but was cancelled in the concept stage due to the system’s poor sales.
The game was never officially announced, the only traces of its existance come from a former Hudson developer on Twitter, going by the handle of @nori_bomber. Check out a collection of tweets here.