Didn't people believe at some point that moon landings themselves caused the Moon to vibrate or something along those lines? Always found that eyebrow-raising.
You might be thinking of impactor probes, in which a vehicle is deliberately crashed into the moon (or another body) in order to generate shockwaves. Previously landed seismic instruments can us this to gather information about the moon's internal structure.
The ascent stages of the Apollo Lunar Modules were deliberately crashed onto the Moon to generate shock waves to support seismology experiments:
Also, for the record this was explicitly discussed in the OP...
There is a "hollow moon" conspiracy theory where one of the pieces of evidence cited is that the moon rang like a bell because of the impact of the lander.