Make the Popcorn: Heat the oil in a thick-bottomed pot on medium high heat. Put 3 or 4 popcorn kernels into the oil. When the kernels pop, add the rest of the popcorn kernels in an even layer. Cover the pot. Once the popping slows to several seconds between pops, remove the pan from the heat.
Melt the butter in a large pot.
Once the butter has melted add the 4 cups of marshmallows and stir until melted. Remove from heat.
Mix in the popped popcorn until thoroughly coated with the marshmallow mixture.
Mix in colored sugar sprinkles, mini marshmallows and M&M's
You can spread the mixture on a tray, allow to cool and cut into bars
You can form into popcorn balls
You can just eat in straight from a large bowl.