Avengers: Endgame was one of the biggest movies in the world and set a high mark for the MCU. It was a movie many loved, but even a great film tends to leave a few unanswered questions. Time travel is always a tricky plot point, and ever since the release of Avengers: Endgame had fans scratching their heads concerned about Pym Particles. This technology was created by Hank Pym, the original Ant-Man, and is instrumental in allowing the Avengers to traverse time.
Update May 8, 2023: This article has been updated with more information in the MCU following the release of Ant-Man and the Wasp: Quantumania and Guardians of the Galaxy Vol. 3.
The movie makes it very clear without Hank Pym (who was dusted in the end credits of Ant-Man and the Wasp), the Avengers have a small number of Pym Particles to use. Ever since the first Ant-Man, Pym Particles have been a rare material that supposedly could reshape the fabric of reality. The tech fell into the hands of past Thanos after capturing a time-hopping Nebula. The Mad Titan then used it to bring his armies into the future and finish the destructive work his future self had started. Now the question is, since Nebula did not possess enough Pym Particles, how did Thanos manage to bring his army forward?
Thanos Advance Technology Pym Particles
While one might say he uses the Pym Particles that future Nebula brought with her, she only has enough for her return trip back. The 2014 Nebula, who is still loyal to Thanos, uses those Pym Particles to travel back and go undercover to open the Quantum Gate in 2023 so Thanos's ship can travel forward. While the film never makes it explicitly clear, the clues for how Thanos pulled it off are present when he examines the Pym Particles. The full answer to how Thanos used the Pym Particles is on the commentary track that accompanies the movie's digital release. The creative team behind the film has this explanation to offer.
"Now, the obvious assumption being that, Thanos who has a spaceship that can carry his army throughout the galaxy and conquer planets can also figure out how to... Science it up a little.... Add some Pym Particles... with his magician who can move matter."
The explanation does hold water. After all, Pym Particles is a breakthrough by human standards. It has been established that Thanos comes from a far more advanced civilization. He also has Ebony Maw at his beck and call, a being who can reshape matter. It is not too much of a stretch to say that Thanos would be able to reverse-engineer the Pym Particles and create more for his own use. Unlike The Avengers, who travel individually, Thanos just needs enough Pym Particles for his ship, which is the object shrinking with the particles. Everything inside the ship, when shrunk, also shrinks with it, as was shown in the multiple shrinking vehicles in Ant-Man and the Wasp.
Guardians of the Galaxy Vol. 3 also introduced the villain, The High Evolutionary. The 2014 Gamora variant that is currently in the MCU knows about the High Evolutionary. Thanos and the High Evolutionary might have crossed paths in the past. Maybe Thanos enlisted his help in cracking the code to Pym Particles. This certainly would make for a great episode of What If...? if Marvel ever wanted to expand on the story.
Pym Particles Blew Open The Door For The Multiverse Saga
In the four years since the release of Avengers: Endgame, the idea of time travel and multiverse has now only become more important to the MCU. After all, Phases 4 through 6 are now dubbed The Multiverse Saga. Once the Pym Particles allowed the Avengers to traverse time and alternate realities, the multiverse has been explored more in projects like Loki, Spider-Man: No Way Home, and Doctor Strange in the Multiverse of Madness. Those projects have introduced new ways to explore the multiverse without Pym Particles. This includes advanced technology, magic, and even superpowers like America Chavez. Yet the Pym Particles still present many possibilities.
In the current Multiverse Saga, we have seen governments and terrorist organizations weaponize the long-believed lost Super Soldier Serum derived from Captain America in The Falcon and the Winter Soldier, She-Hulk: Attorney at Law, and likely Captain America: New World Order. Black Panther: Wakanda Forever showcased how the search for Vibranium has impacted the world and likely will be expanded upon in Thunderbolts. Pym Particles have incredible power, and it is reasonable to assume they can be used in projects like Fantastic Four and Avengers: The Kang Dynasty.
Ant-Man and the Wasp: Quantumania Showed How Rare Pym Particles Are
Ant-Man & The Wasp: Quantummania was an important film in the layout of the Multiverse Saga. It expanded on the world of the Quantum Realm but also gave a proper introduction to the franchise's new overarching villain, Kang the Conqueror. Kang is a powerful foe, and the film's end-credit sequence showed a council of Kang variants that threaten the MCU. However, it also established that as powerful as Kang is, he cannot recreate Pym Particles.
A significant part of the Ant-Man and the Wasp: Quantumania rests on the power of Pym Particles. It is revealed that while she was trapped in the Quantum Realm, Janet Van Dyne used some of the last of her Pym Particles to massively increase the size of the core engine for Kang's time sphere. This left Kang trapped in the Quantum Realm, as he could not shrink the core down without Pym Particles. Once Scott Lang appeared in the Quantum Realm, he finally had what he needed.
This tidbit of information questions the technical prowess of Kang since he didn't know how to override Hank Pym's earthbound technology with his own tech, requiring Scott's assistance to overcome the singularity created by Janet years ago. As of this moment, Thanos was the only one able to tap into the power of Pym's particles. This raises the question of exactly how powerful Kang is compared to Thanos and if he can live up to being the ultimate MCU villain.