Neptunium is the last element named after a place to get a Fun Flag on the this blog. Like the other Fun Flags named after places, the Fun Neptunium flag gets its design from the persons who were responsible for discovering these elements. It was a dynamic duo of men; one was from California and the other was from Washington State.
Consequently the California style flag is used, but fused with colours and elements from the flag for Washington State. Instead of a red bottom stripe, this flag has a bottom stripe the colour of Washington State, which is deep green. Washington's portrait has been modified. He is now on a seahorse carrying Neptune's Trident, near the bottom of the sea. The pose and likeness of this flag was taken from the designs of Washington on horseback from the supposed handkerchief of Washington ordered at John Hewson's calico print shop in 1776. Thus the flag of the Fun Neptunium flag fuses the overall design of the California State flag, Washington State flag and a historical artifact from 1776.
Neptunium's primary father from California was Edwin McMillan and the other dad was Philip H. Abelson from Tacoma, Washington. Note that Neptunium was discovered before the Great War with Ninjas and Nazis, as it was 'officially' discovered in 1940.