try a new project
create one sprite with fade behaviour > name it objSprite
set the fade properties to active on start < no
fade out time > 8
now in the event sheet
system > on start of layout | objSprite > destroy
system > every 2 seconds | system > create obj sprite [layer = 0, x= random (WindowWidth), Y= random (WindowHeight)] //the order of the actions is important
add action > objSprite > set fade in time = random (0,5)
add action > objSprite > Fade: start fade