One can’t be too sure…
Well it’s definitely not a bird due to the lack of feathers. And what one might think is a mouse tail is actually innards in what appears to be the remnants of the intestine family. The thing on the left resembles a femur bone. Or a very thick spinal cord. I can’t be certain. I’m going to go with baby bunny, portly frog or the teacup poodle in 3B.