Me I like hob, I mean we got a new shiny ball before a new raid or new gun or even a new armor shader
-
Well since it is at one of the tables in the Cryptarch area, and it is purple, we can easily assume that it is where all the purples our engrams would have given us go, and the rare chance one doesn't make it into the purple ball, you get it. So maybe THE legenadry ball?