I'm deep in the Symbiote hell too, so tell me how does Wraith look :D?
Oh, assuming you are speaking about a situation when Cassi and Wraith is a one whole big toothy Wraith… I sadly don’t have much art done with them in this state, but here you go, what I was able to find.
Basically black, humanoid in shape and only moderately buff-er and bigger than Cassi is, has that slimy-gooey hair, mandatory teefs and so on. Unhinges jaw and devours the cheese wheels in whole. The only true Skyrim experience.Specializes, I guess, in somewhat stealthy approach to kicking asses, gotta go fast, gotta go silent and gotta get them brains and chocolate.
Sorry if I got your question wrong!