Film Theory: The Rat That Beat Thanos! (Marvel Endgame)

There are TONS of characters that show up in Marvel's Avengers Endgame. Most of them get at least one moment to remind the audience of why they are an awesome superhero and that we should be happy they are alive again. Now, the MVP of the episode is pretty obvious, but I want to talk about the one, tiny hero you probably missed. The rat. Which rat? Why the rat that brought back Ant-Man and made it possible for the Avengers to save the... ?