Since no one else seems to have heard of Black Rainbow.
In the show Z Nation (zombie themed), Black Rainbow is a 4th strike weapon (when 3 strikes aren't enough) designed to destroy all remaining life on planet earth by releasing a bunch of miniature drones that take the shape of a rainbow to drop their payload of flesh eating chemicals.
Although in the context of that note it seems more like a nickname that may have nothing to do with that particular reference (other than taking the symbol of a rainbow and turning it dark).
[–] RookXPY ago
Since no one else seems to have heard of Black Rainbow.
In the show Z Nation (zombie themed), Black Rainbow is a 4th strike weapon (when 3 strikes aren't enough) designed to destroy all remaining life on planet earth by releasing a bunch of miniature drones that take the shape of a rainbow to drop their payload of flesh eating chemicals.
Although in the context of that note it seems more like a nickname that may have nothing to do with that particular reference (other than taking the symbol of a rainbow and turning it dark).