When you tease a kitten with a laser pointer, the beam dot is moving in ways kitten-brain-physics can't comprehend and has to read as a lifeform. Why would you you so confuse a poor critter?
The answer "it's very funny" should not be ruled out.
I'm not convinced the cat is confused into thinking it's a life form, though there is perhaps some confusion due to the non-material nature of the dot. My cat knows that I control the laser and complains to me if I turn it off too soon.
The answer "it's very funny" should not be ruled out.