There isn't much to be shown on the turret so its hard to tell, though that isn't stopping me from looking to see what it is or what it possibly could be. The closest match I've come across so far just from the looks is a KV-85. I'll keep researching and get back on this.
The mantle reminds me of the IS-2 but I can't see the big hatch to confirm although judging from that small viewport in the left, but given the IS-2 and T-34-85 have rather similar turret tops, I guess the mantle will probably give room.
I think its a IS-3.If you look at pictures of it from above you can find the same periscope on the right and it also explains why it has a bulge on the left side of the turret.