Later, after I got home from Venice and started going through all my photos, I missed it in all the numerous images I'd shot.
Then, once I got the picture up on a big monitor and zoomed in, I realized that what I was looking at was a clever piece of improvisation.
This is a "do it yourself lama".
There are a few different terms used for the metal piece which adorns the tail of a gondola, one of them is "lama da poppa", or simply "lama".
Taking a closer look, we see that the tail-piece here appears to have been fashioned out of bendable rail-trim. I'm guessing by the color and felxibility, that the guy who made it used aluminum trim, but it could be stainless steel.
Whatever the case, the guy gets recognition here for solving a problem with creativity and some raw material.