As much as I'd love a hatchling "incubate" BSA, I've seen this suggestion pop up before and TJ has stated that if a BSA like this would ever be released, it would NOT stack with egg incubation; it'd be one or the other, which severely neuters the usefulness of this suggestion.   Personally, though, I could have use for a BSA like this as I'm a regular Siyat catcher, and we all know how you only incubate them if you want a green Siyat. And maybe it could be useful on eggs that are so lo