Sirens - When an opponent conquers a coastal regions (adjacent to a Lake or Sea) occupied by Sirens, the opponent immediately gains 1 coin, but also loses 1 token. If only one token was used to conquer the region, then the conquering race will have no tokens in that region.
I basically ditched this because I don't think it works to have additional disincentive to conquer a region beyond the number of tokens required to do so. Token count is so important, and even an extra coin probably doesn't make up for a lost token.
- Giant Spiders