There used to be a time where it was a trend on social media platforms to post video's about vacuum cleaners battling each others balloon with a knife. Though it is probably a familiar example it is still interesting to look at why this example works so well.

There are 3 main elements that make this play work. 

1. The machines have a clear vulnerability, the balloon.
2. It has a clear weapon: a knife that is aggressively being pointed at the front of the vacuum cleaner.
3. The familiar movement of the cleaner is transformed to a search for victory.

Through these elements the viewers engage very much. You feel both the vulnerability to loose as the temptation to win. The uncertainty of the movements of the machines also provide unexpectancy.

Also, from the movements it makes we humans see a certain intention. Either avoiding, attacking, .... or just being stupid

Another exemple that demonstrates this are Battle Tops. Here several spinning disks start battling with each other. The Tops behave like single individuals moving and striking with each other. Once one start to shake it is a sign that it has become weaker and will potentially soon fall.

Compared to the first example the vulnerability and attacking part are now in 1 tool only: the disk. And the uncertainty now comes from the physics of the playing field. That is why I would consider the first one to be more engaging since it is something that a human can more connect to. It shows more human features. Whereas the second one can be seen more from a distant without too much connection.