Molecule Kid:
Season 1, Episode 8.
Black Widow brings Hawkeye into a covert S.H.I.E.L.D. mission to capture who they thought to be Molecule Man but it turned out to be his son instead hence the episode title.
It is funny the efforts made to keep Iron man out of this mission an attempt that was ultimately unsuccessful.
Interesting that after the resolution of the main core of the episode comes the prospect Molecule Kid, son of a villain, becoming a hero.