Their tour now features props like a giant death's head and alien pods which give birth to them one by one, or at least that is the plan. The love triangle involving Nigel, David and Jeanine is never overtly acknowledged. In an early scene, Nigel and David have lip rings. In a later scene, they have scars from the unsuccessful piercings. The biggest laugh in the second half of the film is assembled lovingly, over time, out of many small elements.
Bad communication causes an error in scale.
To appreciate the skill of Reiner and his editors, observe the way they prepare for the payoff. Instead of simply showing the erroneous prop descending from above, they include a scene where we are told what will happen. Then, after intermediate footage to create anticipation, we see the disastrous moment. Many musicians must go through that early stage when they want to pinch themselves because of their good luck. It's the supreme pipe dream of our era.