I am lighter than air but a million men cannot lift me up, What am I?

Why this works

The riddle plays with the concept of weight and buoyancy. A bubble is indeed lighter than air because it is filled with gas, making it float. However, the riddle emphasizes that even though a bubble is light, it is so fragile that a million men could not lift it without popping it. This clever twist highlights the paradox of something being light yet impossible to physically lift intact!