From the “Puns, Puns and More Puns” site. The author is not known.

My friend Doug came up with this one on the spur of the moment when we were walking across campus several years ago.

He pointed up at a bird-circling overhead and said, “Look, it’s an eagle!”

“That doesn’t look like an eagle”, says I.

“Well of course not”, he shot back amazingly quickly, “it’s traveling incognito, don’t you know that . . . Eagles are Masters of De Skys!?”