Behind us, Blarg bursts out through the front of the Home Depot, bringing down the walls. It’s about as loud as a marching band falling off a cliff.

What does "marching band falling off a cliff" mean?

Question

Behind us, Blarg bursts out through the front of the Home Depot, bringing down the walls. It’s about as loud as a marching band falling off a cliff.

What does "marching band falling off a cliff" mean?

Answer

A "marching band" is basically a military band, with many brass instruments like trumpets, tubas, trombones etc. It also would have drums. The point is that a band like that, with all those instruments, would make a lot of noise if it fell off a cliff!