Hi Bendeng:
First of all, you are very welcome to CavalierTalk. icon_welcome
I've removed the link to your video and I want to explain why. Having watched it, I think maybe you should go back and look carefully at how your puppy is responding and her facial expressions and body language. She is clearly quite upset and anxious, and this isn't helped by the fact that she is also trying on her new boots and initially feels like she can't get away because she is a bit afraid of walking in them. You generally need to gradually introduce a dog to boots in a gentle and positive way (eg rewarding her with small treats for wearing them for brief periods, and maybe starting her with only two feet in them). But she is trying to deal with two disturbing things at once and her body language -- tail down, ears down, shifting anxiously, looking to the person filming for reassurance that she doesn't get indicates she is really quite scared and unhappy. The flipping toy then really scares her enough for her to eventually bolt.
One thing you really never want to do is deliberately frighten a young dog especially when she is clearly young enough to be in her formative months. Puppies go through fear stages and if they are exposed to things that really disturb them at this time, you can have a fearful and anxious dog that will develop long term behaviour problems such as separation anxiety, fear of many normal toys and objects, fear of people. This does not make for a very pleasant dog companion, but worse, this type of fear can very quickly turn into fear *aggression*, where the dog starts to snap. This sets the dog up for the kinds of problems that end up with the dog being euthenised for unacceptable behaviour or left at the pound.
But really, the bottom line is: isn't the video a bit cruel? Does she look at any moment as if she is curious or playful with this toy or rather scared and unhappy and anxious? Does she look like she wants to stay and play happily, or like she'd rather be anywhere than with you, her owner? Wouldn't you be upset if someone you didn't know was doing this to your dog?
I'd have a read of this link:
http://www.diamondsintheruff.com/DevelopmentalStages.html
especially the section on 'Second Fear Period'. Gauging by the video I'd guess your dog falls into this age bracket right now (6-14 months). Here is what this section says regarding what dogs should or should not be exposed to:
This is a fear of new situations and are handled with the utmost patience. The dog is encouraged to work it out on his own. If anything, it is better to ignore the whole situation than to reinforce the fear by praising the dog or petting him while he is afraid. When you "reassure" a dog with pets and "it's okay, fella", you are telling him it is okay to be frightened and you are creating a potential problem.
If your puppy appears apprehensive, avoid confrontation.
Build confidence through training.
Avoid any potentially overwhelming circumstances you cannot personally oversee, such as shipping your pup in the cargo bay of an airplane.
There's a lot of really good information at the site on training and socialising, situations to avoid and things to do to end up with a happy, confident, well socialised cavalier.