Skelespun. Of all the Underbiters, he's the most unpredictable and feral.
Note the scratches and scarring around his left eye; proof of many battles with rats, squirrels and neighbourhood cats. His victories have cost him - he has partial vision or complete blindness on the left side (I can't be sure how serious it is).
Skelespun is a scout, patrolling the territory for intruders. Though his eyesight is impaired, it doesn't effect his agility or skill. This may be because of the tiny spike on his head. It would appear our little friend's cranial appendage acts as an antennae of sorts, similar to the sonic radar of a bat.
Don't bother trying to sneak up on him.
He's nocturnal, preferring the darkness but is drawn to shiny things, collecting them like a crow. If your earring goes missing, or you have a broken zipper, Skelespun is most likely to blame.
Favourite foods include buttons and safety pins.