A Bug Out Bag (BOB) is an emergency grab-and-go bag packed with essentials you'd need if you had to leave home in a hurry.
It's usually designed to keep you going for about 72 hours without relying on outside help.
We're talkin' water, food, first aid, medications, flashlight, emergency shelter, important documents, and other survival essentials.
My brother (USAF) taught me to keep one in the back of my car. I have the same dirtly old purple backpack just in case.