I came up with this jingle in an RP. It's called the Fish-Shaped Crackers Song. It's basically the advertisement jingle of a fictional cat treat product called Fish-Shaped Crackers

You might have to click on 'download' to hear it

The song goes:

Fish-shaped crackers, you're the best!
Much better than all the rest!
If you will give them a try,
We guarantee your cat wont cry!