It's adorable, but also rather disconcerting. Is the faithful dog companion a figment of your imagination? Does he have magical levitation powers? Have you accidentally ingested too much brain fungus while harvesting?
No, Bethesda just has problems making all its 3D models work well together with its physics engine. For no apparent reason, the dog will suddenly switch to a paddling motion as though going through water, but while stuck in mid-air above the ground. This bug is beyond hilarious and just plain fun to watch. Is this a Facebook meme yet?