Sixteen years ago, Bill Watterson ended one of the world's most beloved comic strips. 'Calvin and Hobbes' set a very high bar for every other strip in the comics section with its deep philosophical, gleeful depictions of childhood and vibrant cartoon hilarity. Thankfully, Mr. Watterson has not put down his pen and brush forever.

Fellow comic strip artist Richard Thompson of 'Cul de Sac' fame was diagnosed with Parkinson's disease in 2009. So he started a fundraising project called Team Cul de Sac to raise money for Parkinson's research by asking other artists to contribute works celebrating his comic strip and putting them up for auction. So far, he's received contributions from 'Cathy's' Cathy Guisewite, 'Doonesbury's' Gary Trudeau and 'Beetle Bailey's' creator Mort Walker.

Then a few months into the project, Thompson's editor Caty Neis said she got a package in the mail from Watterson. She told The Washington Post that she couldn't believe the name she was seeing on the return address.

“I have been carrying it around and showing everyone. I didn’t get my hopes up that [Watterson] would contribute. ... Just the fact that this is first art that we have seen from him in 16 years is just so exciting, and what a great cause.”

The oil painting of the comic's main character Petey went up for auction earlier this month. A collector bought the rare work for more than $13,000.