I opened a hobby box of this set yesterday, and every pack contained a rainbow black parallel. These are SN 100 and according to the package seeded 1:16 packs. The packs still contained the normal pulls of others inserts/parallels. Basically each rainbow black parallel was replacing a normal base card. While I am working to build the base set, it was pretty neat to keep pulling one of these cards out of each pack. By the end of the box it was simply "ho-hum, another rainbow black parralel." Not sure why this happened, but it was pretty fun to open.