The Boom Cone is a treasure that is exclusive to the NTSC version of Pikmin 2 that is actually a firework cone. It can be found on the 5th sublevel of the Glutton's Kitchen, usually it is laying in an alcove. It is the 134th treasure on the List of Pikmin 2 treasures in the NTSC version.
Captain Olimar's Journal
"Today we found the remains of a wooden construction engine buried deep under the surface. I can't imagine anyone on this uncivilized planet inventing anything. We'll have to wait until later to finish surveying this maze, but this place intrigues me. There may be something interesting to learn about this primitive object."
"This will exhilarate your soul like magical popcorn! KA-BOOOOOM! Happiness explodes from within. The shape itself speaks of wondrous things to come. Let us get excited!"