The audio quality is not great.
And since the flash relies entirely on a dialogue-based joke, this is a debilitating flaw. The background music makes it almost impossible to hear Navi talking. Then, when the music cuts out, Navi starts talking in a demonic voice which is almost impossible to understand.
On top of all this, the entire flash is only about 15 seconds long, so there's nothing particularly memorable about this flash. I gave you a 2/5 because you made some effort, but you have to make your flashes a lot longer if you want to stand out from the crowd. Or, if you prefer to make one-joke flashes like these, you have to make absolutely sure that the delivery of the punchline is perfect.