In Into the Spider-Verse, Spider-Man variations were atomically unstable in another reality; why didn't this happen in No Way Home?
In Spider-Man: Into the Spider-Verse, Spider-multiversal Man's versions are atomically unstable, while the two Spider-Man incarnations in Spider-Man: No Way Home are not, raising the question of why. Before the MCU brought all three live-action incarnations of Spider-Man together in No Way Home, Sony's critically praised animated picture brought Spider-Man variations from separate universes to the big screen for the first time in 2018. Because of what brought the various Spider-Man variations together, the two films illustrate such varied repercussions of multiversal travel.
After witnessing the sad death of the original web-slinger following a confrontation with Kingpin, who attempts to tap into the multiverse with a Super Collider, Miles Morales, who was bitten by an identical genetically altered spider as Peter Parker, takes over the mantle of Spider-Man. The gadget transports several Spider-Man variations to Morales' home reality, each with a condition known as "glitching," in which their atoms are extremely unstable. If the variations do not return to their original realities, they will perish, presenting another problem for Miles Morales' Spider-Man.
How Did Gwen Return To Miles Morales' World In Spider-Verse 2?
No Way Home puts Tobey Maguire and Andrew Garfield's Spider-Mans, as well as some of their respective adversaries, into the Marvel Cinematic Universe, however none of the characters suffer from the same atomic disease as the versions in Into the Spider-Verse. This is most likely owing to the Kingpin's Super-Collider having a different effect on Spider-Man variants than Doctor Strange's multiverse-altering spell, with the latter's magic offering a considerably easier transition between realities for the two Spider-Men and their opponents than the former's technology. Miles Morales may meet with Peter B. Parker and Spider-Gwen in Spider-Man: Across the Spider-Verse (Part One) without fear of "glitching," thanks to a new mechanism for Spider-Man variants to travel across realities without facing a painful death.
Kingpin is desperate to meet identical multiversal replicas of his murdered wife and kid in the Spider-Verse, so he commissions the Super-Collider from Doctor Octopus and other scientists. Despite the fact that Doctor Octopus is one of her reality's best scientists and is more than capable of developing a more stable gadget, Kingpin's tight deadline for her to finish the machine leads in a machine that risks both their reality and the lives of any multiversals drawn into it. Unless they return to their home realities, Peter B. Parker and the other Spider-Man variations will eventually disintegrate.
Doctor Strange, on the other hand, introduces six supervillains and two Spider-Man variants to the MCU as a result of a reality-altering spell that went awry when Peter Parker tried to change its effects multiple times. Doctor Strange's magic, as a well-trained Master of the Mystic Arts, is stable enough to bring characters into the Marvel Cinematic Universe without causing them to disintegrate. The Macchina di Kadavus, Strange's simple way of sending everyone back, nearly destroys the multiverse when it is destroyed by one of the Green Goblin's pumpkin bombs.
It's uncertain how the multiversal Spider-Man characters will rejoin in Spider-Man: Across the Spider-Verse since Kingpin's Super-Collider was destroyed at the end of Into the Spider-Verse. Something about the destruction of the Super-Collider must have altered the fabric of reality enough to allow web-slingers to travel to alternate universes without "glitching." Doctor Octopus and others may have learned from the initial Super-faults Collider's and improved its stability. This would bring the Spider-Man iterations back together without the dangers demonstrated in Spider-Man: Into the Spider-Verse, similar to the multiversal travelling in Spider-Man: No Way Home.