It's pumpkins all the way down!
This stack of jack-o-lanterns is ~8.5 feet tall, requires about a day and 1kg of material to print the whole thing.

The files are sorted into 5 sets, each set representing every 5th pumpkin in the stack so that they nest together on the build plate. You'll have to print all 5 sets before you can start stacking. Or split the parts to objects and print just the sizes you want.

Each unit has a set of locking tabs on the bottom to add stability and prevent the stack from falling over. The tabs on the smaller units are a little finicky to insert, but should go in without too much fuss.

As can be seen from the photo, each layer provides a bit of opposability, so you don't have to settle for a straight vertical stack.

These should be printed with .4mm nozzle using the standard quality setting.