Watch the episode where most of the cast regulars are involved with an old time murder mystery type radio show called "Nightmare Inn." With little notice, Frasier has asked Niles to take on the parts of several odd characters, including Peppo the Dwarf. Struggling to come up with a suitable voice, Niles grabs a full balloon that was attached to a helium tank, sucks in the balloon's contents and says his line in a Munchkin-like falsetto. The problem lies in the fact that there are 8 to 10 identical balloons lying on their sides next to the tank. Clearly they are not filled with helium, otherwise they would be floating. So Niles's voice was raised by inhaling plain air.