Report 23521: Parked trucker has frightening early morning encounter off I-90 near Wallace

i was truck driving for swift transportation in 1996 it was early summer i was on I-90 just before wallace idaho it was about 3:00 am and i thought id get a few hrs of sleep so i pulled of of the freeway on the forest service off ramp left my sleeper windows open laid there about 15-20 min. the truck was shut off then i heard and felt big hands grab the cab and sleeper bars and shook the truck about 2 times then 3 times just short gentle shakes then a semi truck started rocking side to side like it was a rag doll i jumped up and quickly looked out of the passengers side window just in time to see a dark reddish brown creature take 2 strides into the young douglas fir trees and it was gone, the only thing was i was parked about 20 to 30 feet from the tree line i was so shook up i drove to billings mt. before i would sleep once more , if there are any more questions i would be glad to talk to someone over the phone.