Quoted from PinMonk:
Here's the best topper I've found for PotC. You can wire up the eyes to light up in concert with the machine if you want since it already has lights in the eyes...
Available on ebay all the time for $20-30 on auctions like this:
ebay.com link: Disney Pirates of the Caribbean Talking Skull Jack Sparrow Light Up Red Eyes
PinMonk I have this exact same topper for mine. Thought about adding a model of the black pearl or something to go with it.