Hi there, @Obed_Barrientos and welcome to the Community 
We already have a request for the visualizer feature, and you can upvote it here -Waveform visualizer.
Regarding custom options, we offer various templates with different theme, including a Halloween theme, that you can choose from when creating a widget:
Additionally, you can select the “Custom Theme” option and upload your own background image to better reflect your vibe through the widget:
Feel free to check it out and let me know if any questions come up 