Imagine that your beloved father has passed away and you want to honor his memory in some fashion. But how? Paintings are so pedestrian, and everyone knows a bust is nothing but a surefire way of setting him up for an eternity of boob jokes and barely suppressed chortles. Luckily, you have the perfect memorial in mind:
A naked dude molestin' a turtle.
Also known as a "dick-down rodeo."
Yes, Burnside Fountain, also known as Turtle Boy for no-shit-related reasons, is very much a memorial. Turtle humping probably wasn't part of the original plan; it entered the equation when the artist that was supposed to sculpt the piece passed the gig to his protege, who was evidently just tinkering with sculpting to pass the time until deviantART came along.
The end result of this unfortunate process was revealed in 1912 and has since enjoyed cult status as one of the most skull-crappingly stupid things in existence. Really, the turtle's expression says it best:
"Squirtle, I choose you!"