The Opera-Matic is a failed invention shown only in "3 Squares and an Ed" when Eddy stumbled upon this invention in the Cabinet of Failed Inventions and turned it on for no good reason. When Edd saw what he did, he panicked and turned the machine off, causing the machine to sputter and break down. Its only known function is that when it's turned on, an opera song is played, and it has a functioning flashlight, megaphone and light bulb. The reasons why this machine was a failure is unknown, though Edd's reaction to it being turned on suggests that it is possible the machine was somehow dangerous. However, if you listen to the opera being played, it sounds off-key and out of tune, so it's possible that the machine just plays operas incorrectly and poorly, making them sound bad, so it may just be that the machine is a complete failure at what it does.