I've had some fun before posting strange relationships from Ancestry's OneWorldTree
Lucille Ball being the grandmother of her husband, Desi
Catherine the Great being the 19th great grandmother of Henry David Thoreau (even though less than 100 years separate their births.)
But doing some 'fun' research for a friend I came across something new. This is the supposed relationship of my friend's ancestor Aaron Baldwin, with Henry David Thoreau. (One line of the genealogy chart ran off the page -- Aaron and Henry would have been next.)
Apparently, OneWorldTree allows you to say Person A is the grandparent of Person B, and indicate that a non-existent person fits inbetween. And as you can see on the right, they also allow "great-grandparent." I wonder what maximum number of 'missing steps' are permitted.
(Note: Aaron Baldwin's middle initial is most definitely M, but the parents of Aaron P on OneWorldTree match my research.)