This one is extra fun! Luckily my poly only has 24 instances, and not 1023.
Anyway, if you have a poly~ object referencing an open max patch, and that patch has a subpatcher open, upon saving the patch, you'll get X windows of the subpatch displaying on your screen - locking up your computer while they spawn. X is the number of instances your poly~ object uses.
So, I have patch "Zebra" with a [Poly~ moose 24] open. I have the file "moose" open, and am editing a subpatch ("monkey") in "moose" - when I save "Moose", I get 24 copies of the "monkey" subpatch displaying on screen.
(also sent to firstname.lastname@example.org)