Well the emote isn't specifically for the Reaper's Bones - it was for hitting 10 (roman numeral = X) million players. That is a neat coincidence though.
Jusey1z
Marauder
Insider
Eh. Reaper from Overwatch is a boring "DIE DIE DIE" emo character... I don't see any reason to reference him. He is only good when being made fun of.