Warning: Spoilers for Immortal X-Men #4 & X-Men: Hellfire Gala #1 ahead!
During the years that X-Men hero Emma Frost was a supervillain she did many terrible things, but the worst may have been purposefully killing young Firestar's horse Butter Rum, an act that she is desperately attempting to atone for in modern Marvel comics. Frost's terrible treatment of Angelica Jones not only turned her away from the Massachusetts Academy but made the young mutant fear all other mutants including the X-Men, something Firestar is finally just starting to overcome.
Angelica Jones, the mutant named Firestar who uses ambient microwave energy to fly, melt things, and create fire, was first introduced in the popular animated series Spider-Man and His Amazing Friends, but didn't become a part of the comics until years later. When Firestar finally joined the Marvel Comics universe in Uncanny X-Men #193 she was quickly found by Frost, who at the time was the hyper-villainous White Queen of the evil Hellfire Club. Emma Frost was one of the X-Men's most formidable villains and the Hellfire Club was constantly trying to obtain new, powerful mutants to compete with the Xavier School. As a result, Emma did an incredibly good job of convincing Angelica that she loved and cared about her, when in reality she was just using her.
In Firestar #2 (1986) by Tom DeFalco and Mary Wilshire, Angelica is shown to have grown incredibly close to a stable horse named Butter Rum, but tragically later in the issue Butter Rum's stable catches fire. Angelica saved the horse, only for it to immediately collapse and die. It is revealed that Emma Frost pre-set the fire to burn and then telepathically caused Butter Rum to have a heart attack, all to make Jones think that she caused the fire and killed her horse! Firestar eventually finds out, almost kills Frost, and then flees from her, later joining the New Warriors and the Avengers, but never fully trusting mutants again. Now, in the pages of both Immortal X-Men #4 - written by Kieron Gillen with art by Michele Bandini - and X-Men: Hellfire Gala - written by Gerry Duggan with art by Kris Anka - Frost not only acknowledges her horrible murder of Butter Rum, but tries and fails to reconnect with Firestar.
In Immortal X-Men #4 as Frost prepares for her Hellfire Gala she reflects that she "...made a girl think she'd cooked her own horse so she'd come to me for sympathy," before acknowledging that she was a mess back then and in her "snow phase," a clear reference to her copious amount of cocaine usage during that era. Emma has been attempting to atone for her past sins as a supervillain for decades, ever since becoming a teacher and leader of the X-Men, and while she has found peace and resolution with other enemies of hers like Jean Grey, X-Men: Hellfire Gala shows that this has not happened with Firestar. At the Gala Emma attempts to have a nice conversation with Angelica, telling her that she is a hard woman to apologize to. Firestar remarks that much of the reason why the mutants of Krakoa don't like or respect her is because of Emma Frost manipulating her into not trusting the X-Men, which has led to her rarely reaching out or connecting with her fellow mutants. As Angelica walks away Frost, seemingly speaking to herself, says, "I wanted to show you the stables at Hellfire Bay," a clear reference to Butter Rum, and apparently the way that Emma was hoping to atone for her sins with Firestar and her beloved horse.
Emma has one of the most impressive redemption arcs in all of X-Men comics, but it is clear that Angelica is still not in a place where she is able to forgive Frost's sins against her. But hopefully now that Firestar is officially on the new X-Men team, she and Emma Frost will be able to get over their differences and move on from the death of Butter Rum.
Immortal X-Men #4 and X-Men: Hellfire Gala are both available in stores!