Your answer is in the manual.
How events work
is the fact that the event sheet is read 60 times per second.
And each condition that is true is executed.
So what you have done is basically spawning objects 60 times a second.
In 2 seconds you have 120 object.
In 60 seconds you have
And each of those times, you are creating duplicates of the object when you should be creating objects only once.
Actually make a Function that you call when you click, it will create a single object at the moment of clicking instead of "every tick".