Marvel Unlimited features an overwhelming amount of acclaimed and historic comic book runs. The most influential comics are constantly spoken of because of their influence on the stories that followed. It's easy to miss the comics that didn't have much of an impact. As a result, the non-canon anthology series What If...? could be the most overlooked series.

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What If...? created new tales by changing one detail in famous stories. The first volume of What If...? lasted 47 issues with the second running for 115 issues. Marvel would frequently revive What If...? for a miniseries or a special feature. You can't read every single issue of What If...? on Marvel Unlimited, but there are many issues to choose from, including some real standouts.

10 What If...? (Vol. 1) #7

By Don Glut, Ron Hoberg, Sam Grainger, George Roussos, And Rick Parker

Betty Brant displays her spider powers to Peter Parker

"What If Someone Else Besides Spider-Man Had Been Bitten By The Radioactive Spider?" was an early issue that proved that the series had a lot of potential. After Uatu's brief introduction of Spider-Man's origin, he told three stories with alternate outcomes.

Flash Thompson, Betty Brant, and John Jameson all got spider powers with very different results. There's a lot of story in a single issue, and it not only explored supporting characters, it gave insight into who Peter Parker would be if he never became Spider-Man. No matter what, he always felt a sense of responsibility and the need to live up to his full potential. And, like all great Spider-Man stories, there was an element of tragedy.

9 What If...? (Vol. 1) #27

By Mary Jo Duffy, Jerry Bingham, John Stuart, Carl Gafford, Artie Simek, And Janice Chiang

Phoenix fights alongside the X-Men

"What If the Phoenix Had Not Died?" sprung from one of the most famous X-Men stories of all time. In the original story, the X-Men defeated the Imperial Guard with Phoenix's power, and she chose to give up her life. In the What If...? issue #27, the Imperial Guard won and stripped Jean Grey of the Phoenix power.

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Jean was given a poignant internal struggle in this issue. Jean's Phoenix powers returned, and she grew distant from her friends and family as her power grew. Jean became corrupted and did some horrific things. This issue's tragic ending proved that What If...? wasn't afraid to go to some dark places.

8 What If...? (Vol. 1) #34

By Fred Hembeck And Bob Layton

Uatu watches other versions of himself

What If...? established early on it could do tragic and it could do dark. It took until issue #34 when the series proved that it could do funny. "What If The Watcher Were A Stand-Up Comedian?" introduced a silly version of the Watcher only interested in amusement.

Written and drawn by pretty much every talent Marvel had at the time, the entire issue was composed of quick gags. Not a single Marvel character is spared, as Thor had a Swedish accent, Cyclops' blast came out of his ears, and Aunt May became Ant-Aunt. The final page of the comic was Stan Lee finding out about it and firing everyone.

7 What If...? (Vol. 2) #4

By Danny Fingeroth, Mark Bagley, Keith Williams, Tom Vincent, And Ken Lopez

Spider-Man with symbiote attacks the Hulk

Venom became one of Spider-Man's worst enemies due to the hatred Eddie Brock felt for Peter Parker. "What If The Alien Costumed Had Possessed Spider-Man?" suggested that the real nightmare wasn't Eddie Brock but the symbiote itself. It fed on Peter Parker, aged him to the point of death, and then went on to find new hosts.

The symbiote possessed the Hulk and then Thor while the assembled heroes tried to figure out how to stop it. The real hero of the story was the Black Cat. Grieving over the death of the man she loved, she had to make a choice that would destroy her future to end the symbiote.

6 What If...? (Vol. 2) #105

By Tom DeFalco, Ron Frenz, Matt Webb, And Chris Eliopoulos

Spider-Girl dodges Green Goblin's zap-blasts

During the Clone Saga, Peter and Mary Jane lost the child they were expecting. "Legacy... in Black and White" presented May "Mayday" Parker, a teenager who discovered that she had spider-powers. Harry's son Normie became the new Green Goblin, and Mayday became Spider-Girl just in time to thwart him.

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Comic books love dark futures, but this What If...? succeeded in creating a compelling optimistic future. With her mother's confidence and her father's sense of humor, Mayday had fun being Spider-Girl. The heroes of Spider-Man's day either died or retired, but there were so many legacy heroes that they were spun-off into an entire line of comics called MC-2.

5 What If...? (Vol. 4) #6

By Robert Kirkman, Michael Avon Oeming, Val Staples, And Dave Lanphear

Thor delivers planet for Galactus to devour

"What If Thor was the Herald of Galactus?" began with Galactus feasting on Asgard. He didn't destroy Asgard, but it was left in ruins. Thor wanted revenge, but Galactus convinced him to be his herald.

Thor and the Silver Surfer are both noble, but Thor became a different kind of herald. After failing Asgard, Thor sought to regain his honor by presenting Galactus with savage worlds to feast on. Thor continued to be haunted by his failure to protect Asgard. The What If...? gave Thor a morality debate and a quest to regain his worthiness that hadn't been seen in the mainstream comics.

4 What If...? Featuring Planet Hulk

By Greg Pak, Leonard Kirk, Rafa Sandoval, Gary Erskine, Moose Baumann, Joe Caramagna, Guru-eFX, And Fred Hembeck

Caiera kills Iron Man and Mr. Fantastic

Greg Pak created an epic when he sent the Hulk to the world of Sakaar in 2006's Planet Hulk. Pak returned to the concept in What If...? with two full stories and a humorous back-up.

In "What If The Hulk Died And Caiera Had Lived?", Caiera filled Hulk's role in World War Hulk. A rampaging Hulk is scary, but Caiera managed to be an even bigger nightmare to Earth's heroes. The second story was "What If the Hulk Landed on the Peaceful Planet that Reed Richards Promised?" It raised the question of if a peaceful planet could get Hulk and Bruce Banner to work together. Fred Hembeck's final story was one page where Banner lands on Sakaar.

3 What If...? House Of M

By Brian Reed, Jim McCann, Paolo Pantalena, Allen Martinez, Victor Olazaba, Danny Miki, Scott Hanna, Andrew Pepoy, Guru-eFX, And Jeff Powell

Iron Man calls armored heroes into action

Volume 7 of What If...? was a five-issue miniseries released in 2008. Each issue had a back-up where the Runaways became the Young Avengers. The main story was "What If... Scarlet Witch Ended the House of M by saying No More Power?" where Wanda eliminated all powers, not just those of mutants.

The issue examined what happened to many heroes, not just the mutants, who were given the chance to be normal. The Red Skull got his hands on the Cosmic Cube and only Iron Man and other tech-based heroes fought him. Some heroes who had lost their powers stepped up to fight the Red Skull, proving that heroism doesn't come from superpowers or advanced weapons.

2 What If...? Fallen Son

By Marc Sumerak, Trevor Goring, Elizabeth Breitweiser, And Dave Sharpe

Captain America and other heroes salute Tony Stark

The other great What If...? issue from volume 7 was a re-imagined conclusion to Civil War. "What If...Iron Man Had Died?" killed off Tony Stark rather than Steve Rogers. The events of Civil War played out the same way until Captain America's trial. Tony Stark was killed by an enraged Tom Foster.

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The issue covered those closest to Tony going through the five stages of grief. In the original Civil War, Steve Rogers lost and died a hero. Tony Stark won but had blood on his hands. Through his death, the What If...? made Tony more sympathetic and heroic than the original story.

1 What If...? #200

By Marc Guggenheim, Dave Wilkins, Lucio Parrillo, And Dave Lanphear

The Watchers judge Uatu who has killed Galactus

It took nine volumes and 33 years for What If...? to reach its 200th issue. Norman Osborn won Siege with the help of the Sentry in the first story, and the rest of the issue brought in all-star talent.

Stan Lee revisited his and Jack Kirby's Galactus Trilogy. Dale Eaglesham provided the art for Stan's "What If Uatu Killed Galactus?" Frank Miller wrote and penciled an alternate take on his Daredevil run where Bullseye didn't kill Elektra. The issue also featured a retrospective by Roy Thomas and several Marvel creatives chiming in on their favorite What If...? story plus an art gallery of covers and a check-list of the issues leading up to the big 200.

NEXT: 10 Marvel What If Comics That Went Way Too Far