Whirly--No one can pronounce the wallacatoon's real name, so they call him Whirly because of the way he runs. He has three legs. Or, are they arms? Or trunks? Each has a mouth at the end and a set of eyes at its base.

From the book:

Watching a wallacatoon walk was amusing. Watching one run was spectacular.

Whirly normally moved by putting one appendage out in front of the other two, then drawing the others forward until they were just ahead of the first one. Then he’d bring the single arm forward and start all over. It reminded me of someone walking with crutches. Every so often Whirly would do a quick 1/3-body turn—without breaking stride—bringing one of the rear legs up to the front to give the first one a rest.

Wallacatoons are surprisingly fast on their feet at a normal walk. They are lightening unleashed when they run. Whirly would suddenly plant two feet on the ground, tilt his body up sideways, stick his third appendage into the air, then kick himself forward with the hind-most foot. His starts weren’t quick, but once he got going he truly lived up to the name I gave him. Whirly became something of a self-propelled wheel, spinning along rapidly with one foot at a time kicking him forward.