Pym Particles are fictional subatomic particles from the Marvel Comics universe, primarily associated with the character Hank Pym, also known as Ant-Man. These particles have the unique ability to alter the size and mass of objects, allowing them to shrink or grow at will. In the comics and films, Pym Particles are often used in conjunction with advanced technology, enabling characters to change their physical dimensions. This concept plays a significant role in the stories of Ant-Man and the Avengers, showcasing the potential of science fiction to explore themes of size, power, and identity.