I don't remember ever seeing that video on 3DCG. I think you might be confusing two separate videos, both done by OP, one where a dead Mei is necrod by Genji and another where a dead Sombra is necrod by Roadhog and Junkrat. If there was a overwatch futa snuff animation I'm sure it would have stuck in my head. And there's only a couple of artists there who post their stuff using mega links.