Black Goliath
Trapped at a giant height, Dr. Henry Pym teamed up with Dr. Bill Foster to regain his ability to safely shrink. Dr. Foster would later use Goliath's research to give himself growing powers and become Black Goliath!
Black Goliath got his own series which was promptly canceled after five issues. He guest-starred here and there, changed his name a few times, and even beat cancer, but remained a minor hero. He's now best known for being killed by a cloned Thor.
This was Dr. Foster's first costume, and not his finest.