All my avatars across QQ, FiC, SV, and SB are various humanoid avatar representations of Shub Niggurath. Assuming I don't immediately freak out from now eldritch senses, mind, body, and soul and either kill or mutate everything on the planet and can maintain some semblance or facade of humanity? Even then some interesting and weird stuff happens.
So what you gotta say to your friends,family and others from real life from having a different look with unique powers or something?
To my family: "What you're looking at now isn't even the real me... at least not all of me. It's like this is a communication device that isn't going to immediately cause your mind to self destruct. You all seem so tiny and insignificant now and that's not even an accurate descriptor. I can sense every bit of life down to your cells and the bacteria in the room and dimensions and concepts....", there's a pause as if there's distraction or deep thought for a moment, "I can't describe it any human language. It's beautiful though... like suddenly seeing and understanding the world and everything about it.", another pause followed by staring as I step closer, "I have to go away soon... Let me show you the universe or at least the fraction of what I can make you understand... don't worry, the discomfort won't last long."
So how many events would happen?
I probably end up leaving the planet to avoid completely destroying the Earth and likely end up still causing problems by mutating and spawning various creatures before that happens.
At best I probably end up converting every sapient being in the immediate area into
Gof'nn hupadgh Shub-Niggurath or some form of Goat Spawn in an attempt to uplift them while I still care about that. People go varying degrees of insane by human standards from the physical and mental transformations. If I don't leave all the Earth flames with a holocaust of ecstacy and freedom in the best case scenario.
Bonus event. We are in the Current DC's Universe was summoned by Dr. Manhattan or any of your favorite universes from fiction.
Dr. Manhattan and I stare at each other. There's understanding between us on a level no human can comprehend. If he's the one that caused this transformation I probably thank him to some degree before leaving to explore the universe/multiverse and get a handle on things with him not really being able to stop me, probably ask him some advice first on being what is in effect a god that doesn't think like a human anymore.
Favorite universe... that's tough since I have several.
In the Cultureverse The Culture and the Minds probably end up assuming I'm some form of Sublimed before I show and/or explain I'm something very different. The Minds probably have issue with me being an Outside Context Problem.
Cthulhu Mythos? Possibly merge with, replace, or work with the original Shub Niggurath.
My Hero Academia? Eldritch mutations become a thing on top of Quirks.
Fallout? The wasteland becomes teaming with new, strange life.
Steven Universe? The Crystal Gems freak out in the likely chance that Steven and Connie receive my edritch gifts. I probably attempt to fix the Gem Monsters and make them more dangerous in the process.
Warhammer 40k? The Outer Gods are what Chaos wishes it could be. There's a collective freak out from them when they realize what I actually am. I get a lot of cultists and play around with the galaxy if I care about doing that.