Non-scouting ... a long time ago. I was about 5 or 6. Big canvas family tent of the 70's. I wouldn't call it the worst experience, but probably the most memorable.
My parents slept on the floor of the tent. Me, my sister and brother all had cots. I was closest to the door, my sister in the middle, and my brother against the back wall. I was awakened by my dad reaching in from outside the door telling me not to move or make any noise. He then pointed to under my brother's cot where our groceries were still in their bags, where I saw the black and white tail. (My mom was outside on the picnic table.)
I slowly propped myself on my elbow and watched. During the movement and the noise of peanut shells crunching, my sister (about 4) woke up and began screaming. My dad had to reach into the tent and pull her out. In the process, he ended up tipping over her cot. So my dad had to pull me out, fearing what was coming next. My brother (about 2) was still asleep with our visitor munching below his cot.
Being a large tent, my dad really didn't want to go back in if he could avoid it to pull out my still sleeping brother. We were sitting on the picnic table waiting for the ranger to arrive, when the visitor came out the door, went around the side of the tent and took off for parts unknown.
Thankfully there were no lingering affects as our visitor wasn't frightened in the tent, but had apparently cut its nose on a peanut shell which is what caused him to vacate. After that, my mom started leaving the food in the car.