Report 16527: Multiple witness incident at night near Idaho Falls

On November 4 2006,Me & my family were driveing through the foothills above Idaho Falls near willowcreek when my sister,fiance,daughter&nephew said they had seen something off to the side of the road. I stopped & turned around so I could shine the lights from the bronco on whatever it was. when we got turned around the lights from the vehicle couldn't hit it so I decided to step out with a flashlight when I shined the light on it,it stood up on it's hind legs about 30feet from me.It was standing in a borrow pit and it was at least a foot taller then me,Iam 6 foot tall.When I seen it I started yelling at it & it ducked down every time I would stop making noise it would start to raise its head again.When I backed up & got into the bronco it jumped up & ran after us,& chased us quite aways. We all seen it but we could not make out any facial features.I have heard stories in the past from friends & family of sightings in the same area but never payed much attention.Iam an avid hunter & fisherman. I spend alot of time in the outdoors I have hunted & fished in this area all my life.I have seen elk,deer,antelope,badger,& bear. just about everything that has walked crawled or swimmed. And I have never seen anything like what I seen that night. It was bigger then any bear i have ever seen & I hunt the selway were there is a large population of bear& what we seen that night was not a bear.