It doesn't happen often, but every once in a while, sometimes things from an alternate reality gets brought over to the mainstream universe. Maybe it's because the character is popular, or maybe it's a creator's pet, or it could be any of several other reasons. I've touched on this before here. Today, we have three new examples, this time from Marvel (and one from DC).
The first is Monica Chang, who first appeared as the new Black Widow in Ultimate Comics Avengers #3 (December 2009). She later appeared in Avengers AI #1 (September 2013) as a SHIELD agent.
The second is Geldoff, who first appeared as a Latverian mutant villain in Ultimate Spider-Man #40 (July 2003). He later appeared in the 616 universe as an Avengers Initiative trainee named Proton in Avengers Initiative #8 (February 2008).
Number three is Sophia Sanduval, aka Chat, who first appeared in Marvel Adventures Spider-Man #53 (September 2009), as a mutant who can talk to animals. She later jumped to the mainstream in Spider-Girl #4 (April 2011).
And finally we have Carrie Kelley, the future Robin from The Dark Knight Returns (1985). She made her debut on Earth-Zero as a student at Gotham Community College who had been giving Damien Wayne acting lessons; her first appearance was Batman and Robin #19 (June 2013).