Rebel "singing" in the bathroom?

For the past couple of nights, while I'm watching TV, I can hear Rebel meowing (singing) away in the bathroom.
My place is very small, but with the lights out & only TV on in living room, I still couldn't see what she was doing.
Last night, after Rebel started singing again, I filmed with a flash...
Turns out, she plays with toys on the bathroom floor. Why she needs to "talk" or "sing" to them is beyond me😸
The secret life of cats😄