This Story has scary parts and is meant for Boy Scouts.
Decide for yourself if it is appropriate for your younger scouts or not.

To make 'Old Growler', punch a hole in the middle of the bottom of a large tin can, attach a soft rope about three feet long to the hole, with the length of the rope hanging out of the bottom, 'Tin Can Telephone' style. You can use a couple of washers on either side of the hole to protect the rope from being cut. 
 
To use 'Old Growler', you MUST get the rope wet, hold the can in one hand and run your other hand down the length or the rope using some resistance. 'Get the bears tail wet and stroke it.' 
 
Also you might introduce "Old Growler" to the group immediately after the campfire story, by having someone who has been hanging around out side of the campfire circle sneak off, return with 'Old Growler', and let him ROAR!  
After the initial chaos has calmed down a bit, let the scouts try it out. Be sure to have some water handy to wet his tail. 

Leaders sometimes have trouble getting the scouts, and even some of the Leaders out of the sack in the morning on campouts and at Summer Camp.

The Secret of the Bear 
Did you know that there is a bear out in these woods? His name is Old Growler and he is very hungry. He has a known habit of coming around early in the morning looking for food. Old Growler is hungry but he is not looking for ordinary food, he only eats meat, no other kind of food. Because this bear is old and Old Growler can no longer hunt and kill, like a healthy young bear does, this bear only wants dead or injured meat. 

Old Growler has though, developed a taste for a certain kind of camp food - Scouts and their Leaders, but like I said Old Growler only eats, dead or injured meat. 

If hungry Old Growler comes to your tent in the early morning, looking for his favorite kind of food, namely you, just let him know that you are NOT dead by telling him to "Go away Old Growler, I am not dead, you don’t eat live, healthy meat." But of course, EVERYONE in your tent must tell him this, Old Growler won't leave while he suspects there may be some dead meat in your tent. Old Growler will then go away to look for food elsewhere. 

BUT Old Growler is hungry and will come back, if he suspects there may be some injured meat to be found in your tent. You see, to Old Growler any meat that can’t stand and move around is injured. So if you want Old Growler to go away and leave you alone you must let him know that you're not just injured meat, by making a lot of movement in your tent. Getting dressed and coming out of your tent will always chase off Old Growler. 

Don’t forget, Old Growler can always come back, he is hungry, he is looking for food, he only eats dead or injured meat, and he is coming and looking for YOU!