Dr. Jonas Venture, Jr. is the twin brother of Dr. Thaddeus "Rusty" Venture on The Venture Bros.  Somehow fetus Rusty swallowed Jonas up in the womb and laster Rusty emerged as an adult with dwarfism over forty years later through a stomach tumor.

Now Jonas, with half the claim the Venture empire, took Spider Skull Island and the X-2.  He defiitely got the shaft, but he seems to want to have a good relationship with his brother.

Venture Bros. Quotes

Brock: Someone is in my car!
Hank: Now that's a super power. He can do that from 10 states away.

Venture and I have been engaged in a deadly game of cat and also-cat for years!

The Monarch