which one are you?

"​Mice which have lived to be very old sometimes grow tired of life in the dreariness of the fields. They see the birds and wish to fly. So they migrate through fissures and tunnels down into the bowels of the earth, the underworld. When they emerge years later the finger bones of their front paws have lengthened to support long, thin, membranous wings. The metamorphosis, sadly is not without its price. The enormous size of the wings necessary to lift the weight of their bodies prohibits the poor creatures from maneuvering on the ground, and even to rest they must hang inverted from the upper surfaces of the damp caverns in which they reside. More painful still, they are condemned to live in complete darkness as the long years spent in the absence of light have left them blind. Eventually the memory of their former existence drives them insane."