What does SIM! Mean?
Two parts; the exclamation is just to denote Tony as being SIM, in the usual trait!character format fandom uses to describe alternate versions of characters (Omega!Tony, Alpha!Tony, Mafia!Tony, Poor!Tony, Homeless!Tony, etc) and the SIM part is an acronym for Superior Iron Man which is a version of Tony Stark that is depicted in the comics as being very cocky and arrogant because....uhh...I think magic?
I don’t really remember why his personality gets altered tbh but it does and he becomes so Daddy he nearly takes over the world. It’s great. I think the comic book series is finished? I’ve never actually read the SIM comics, I just read the summary and looked at sexy pictures of Tony in silver and blue armor and fell in love.
Fans have taken the Superior Iron Man alternate version of Tony and run with it though because he’s fucking sexy and evil and we all want to fuck villains around here and he’s become almost a shorthand way to get your itch for evil!tony scratched.
Hope this helped nonnie :)