“ A race of people identical in all respects to humans except for the fact that they lay eggs.”
“ What if some crazy wizard created an artifact that empowered rodents that touched it with one random supernatural power? Preferly right out of the pages of your favorite four-color. (But only one power!) This item does not convey any sort of intelligence boost.”
“ An army and navy who work in the same way as others except their rank titles are upside-down. So people start as full generals and those with the rank of private command armies.”