Magnetic fluid is fun to play around with. As it turns out, you can also use it to visualize music. The SoulBeat Golden Ferrofluid Bluetooth 5.1 Speaker does that and more. It has a 6000mAh battery that lasts up to 12 hours. The front panel lets you adjust the shape of ferrofluid and change sound level & songs.
This speaker is available in various colors. You can interact with it like a regular ferrofluid toy using a handheld magnet.