While it may not be the first thing your kids think about, adults will pretty quickly see the relationship between the Big-Boy Boomeroo and the atomic bomb. Even the name is similar to the bomb dropped on Hiroshima, nicknamed "Little Boy". Sounds like someone had a sense of humor.
The atomic bomb was developed during World War II as a top-secret project. As the tragedies at Hiroshima and Nagasaki showed, the weapon proved to be sufficiently powerful to threaten all life on earth—particularly as the race shifted from a competition between the United States and Germany to one between the United States and the Soviet Union. Complicated? Just a little.
The Big-Boy Boomeroo, Seuss's metaphor for the bomb, is "a gadget that's Newer than New / It is filled with mysterious Moo-Lacka-Moo / and can blow all those Zooks clear to Sala-ma-goo" (165-67). The problem, it seems, is that nobody's sure exactly how it works. It's such a mystery that the Boomeroo can only be described with Seussian (read: not real) words.
Is Seuss trying to tell us that we shouldn't be messing with things bigger than ourselves?