Tahoe Tessie Sighting?

As we were coming back west bound Hwy 50 we just emerged from the cave rock tunnel and my wife made a comment “whats that?” looking towards the lake which was maybe 100′ away, out about approx 50 yards was a shiny black cylindrical thing that was maybe 40′ long it came out of the water in a sort of long twist and then emerged and then out again, no head or tail visible….