Brothers Grimm (Old school breeders) found seeds in a bag of Jack Herer. There were two killer phenos, one ended up being called Genius, the other C-99. They are just reworked Jack Herers and are suppose to be similar to it.
I believe Joey Weed on Hemp Depot has the Apollo 11 which is GeniusxC99. They are sold out of the C99 and I can't find it anywhere online.
I was lucky enough to get some beans from a member on a different forum. They were bred from original Bros Grimm stock, and were bred to F4's. You can follow my grow log in my sig if you'd like. They just went into flower a couple of days ago.
So, like I said, its just a reworked Jack Herer that they preserved the characteristics they loved about those 2 phenos. If you want something similar, look at the Joey Weed strains on hemp depot. They have some crosses of C99, and I'm sure you can pick/breed the ones that are more on the C99 side. And the Apollo 11, as mentioned, is GeniusxC99.
I hope this helped.